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Defect passivation jutiyo kudu lee pi medo tic pa lead triiodide perovskite solar cells, ento adwogi pa defects matung tung ikum α-phase stability podi ungeyere ngo; Kae, nitio ku theori mi tic pa density, wa nwango pi tyen acel yore mi nyoth pa formamidine lead triiodide perovskite kud i α-phase ni δ-phase man wabeponjo adwogi pa peko matung tung ikum phase transition energy barrier. Adwogi pa simulation nyutho nia iodine vacancies copo nyayu ret pilembe gi dwoko piny kero pa α-δ phase transition man gitiye ku kero ma nok mi yubu piny i perovskite surface. Kelo dul ma pek pa lead oxalate ma pii nyai ungo iwi perovskite uketho α-phase utur, ma juku wotho man loko pa iodine. Mi medo, yore eni dwoko piny rwom pa nonradiative recombination man medo kero pa solar cell ni 25.39% (certified 24.92%). Jam tic ma jukwanu ngo copo bedu ku 92% pa kero pare macon ingey tiyo ku tego madit pi sawa 550 i the 1.5 G air mass irradiation.
Ker pa mac (PCE) pa perovskite solar cells (PSCs) utuc i rwom ma malu pa 26%1. Nicaku i 2015, PSCs ma kawoni gimaru formamidine triiodide perovskite (FAPbI3) calu piny ma mako ler pi bedo maber pa lyethu man bandgap pare ceng ku Shockley-Keisser limit pa 2,3,4. Ku gum marac, FAPbI3 films thermodynamically kadhu kud i phase macol ni α phase macol ni yellow non-perovskite δ phase i ot temperature5,6. Mi juku yik pa delta phase, juyubu perovskite matung tung. Yore madit uloyu mi jwigo peko eni utiye mi rubu FAPbI3 ku methyl ammonium (MA+), cesium (Cs+) man bromide (Br-) ions7,8,9. Ento, hybrid perovskites nwango peko mi bandgap broadening man photoinduced phase separation, ma nyayu peko i tic man kero pa tic pa PSCs10,11,12.
Somo ma kawoni unyutho nia FAPbI3 ma leng ma epe ku doping moko utiye ku kero maber ni kum crystallinity pare maber man defects pare ma nok13,14. Pieno, dwoko piny peko ni medo crystallinity pa bulk FAPbI3 ubedo yore madit mi nwangu PSCs2,15 ma tiyo maber man ma ling. Ento, i saa mi tic pa FAPbI3 PSC, nyothre ni yellow hexagonal non-perovskite δ phase copo timere ngo16. Lembe ne caku iwi ngom man i dhu lum ma pii, lyethu man lero copo nwangu pi bedo pa kabedo mapol ma rac17. Pieno, passivation mi surface/grain piretek pi dwoko piny macol pa FAPbI318. Lembe madwong mi jwigo peko, ikinde kelo perovskites ma nok, acid-base Lewis molecules, man ammonium halide salts, gitimo dongo madit in formamidine PSCs19,20,21,22. Nitundu kawoni, lembe mapol ma juponjo uketho wigi ikum tic pa peko matung tung i nyang ikum kit pa optoelectronic calu carrier recombination, diffusion length man band structure in solar cells22,23,24. Ku lapor, density functional theory (DFT) jutiyo kudu pi nyang ikum tego pa yik man rwom pa tego pa peko matung tung, ma jutiyo kudu lee pi telo wi yub mi passivation20,25,26. Ka wel pa peko udok piny, bedo pa jam tic ne bedo maber. Ento, i formamidine PSCs, yore mi tic pa peko matung tung ikum bedo maber pa piny man kite ma ler timo kudu ucikere ni bedu tung tung. Nimakere ku ngec mwa, nyang ma pire tek ikum kite ma peko nyayu ko cubic ni hexagonal (α-δ) man tic pa surface passivation ikum phase stability pa α-FAPbI3 perovskite podi ungeyere ngo maber.
Kae, wabe nyutho yore mi nyoth pa FAPbI3 perovskite kud i α-phase macol nitundo i δ-phase macol man adwogi pa peko matung tung ikum kero pa α-to-δ-phase nikadhu kud i DFT. I vacancies, ma yot ni kelo ikare mi yubu filim man tic ku jam tic, juporo ni bedu ma copo caku α-δ phase transition. Pieno, wakelo lead oxalate (PbC2O4) ma rwinyo ngo i pii man ma rwinyo ku kemikol iwi FAPbI3 nikadhu kud i in situ reaction. Lead oxalate surface (LOS) juku dongo pa I vacancies man juku wotho pa I ions ka juyiko ku lyethu, lero, man kero pa mac. LOS ma wok kud i iye dwoko piny rwom pa nonradiative recombination man medo kero pa FAPbI3 PSC ni 25.39% (juyio ni 24.92%). Jam tic ma jukwanu ngo LOS ubedo ku 92% pa kero pare macon ingey tic i kabedo ma tek (MPP) pi sawa ma kadhu 550 i rwom ma malu pa yamo (AM) pa 1.5 G pa radiation.
Wacaku timo kwanu ab initio ni nwangu yore mi nyoth pa FAPbI3 perovskite ni loko kud i α phase ni δ phase. Ni kadhu kud i yub mi loko dul, junwango ni loko kud i dul adek ma poko [PbI6] octahedron i cubic α-phase pa FAPbI3 ni octahedron ma poko dul acel [PbI6] i hexagonal δ-phase pa FAPbI3 utimere. turo 9. Pb-I timo dul i rwom mir acel (Int-1), man kero pare utuc 0.62 eV/cell, calu ma ju nyuthu i cal mir 1a. Ka octahedron juloko i yo [0\(\bar{1}\)1], hexagonal short chain umedire kud i 1×1 ni 1×3, 1×4 man i ajikine emondo i δ phase. Kite ma yore eca nen kudu utiye (011)α//(001)δ + [100]α//[100]δ. Kud i cal pa poko pa kero, jucopo nwangu niya ingey nucleation pa δ phase pa FAPbI3 i rwom ma ulubo, rwom pa kero utiye piny uloyu pa α phase transition, ma nyutho ni phase transition bibedo pio pio. Mandha, timo mir acel mi jwigo aloka loka pa dul piny piretek tek wabemito juku nyoth pa dul piny.
a Phase transformation process from left to right – black FAPbI3 phase (α-phase), first Pb-I bond cleavage (Int-1) and more Pb-I bond cleavage (Int-2, Int -3 and Int -4) and yellow phase FAPbI3 (delta phase). b Energy barriers to α to δ phase transition of FAPbI3 based on various intrinsic point defects. Lain ma jugoro ku rangi ma nya wange nyuthu kero pa kristal maber (0.62 eV). c Teko mi yubu pa lembe ma pire tek ikum lead perovskite. Abscissa axis ubedo kero pa α-δ phase transition, man ordinate axis ubedo kero pa defect formation. Thenge ma juketho i rangi macol, macol man macol ubedo kit I (low EB-high FE), kit II (high FE) man kit III (low EB-low FE), kubang wadi. d Teko mi yubu pa peko VI man LOS pa FAPbI3 in control. e I barrier to ion migration in control and LOS of FAPbI3. f – lanyuth pa wotho pa I ions (orange spheres) man gLOS FAPbI3 (gray, lead; violet (orange), iodine (mobile iodine)) i gf control (kor cing: nen malu; cing cing: tung cing, brown); carbon; blue ma ler – nitrogen; makwar – yamo; pink ma ler – hydrogen). Lembe ma wok kud i iye jumiyo i ayi pa lembe ma wok kud i iye.
I ngeye wa somo ikum adwogi pa lembe matung tung ma nyayu peko (calu PbFA, IFA, PbI, man IPb antisite occupancy; Pbi man Ii interstitial atoms; man VI, VFA, man VPb vacancies), ma jukwanu ni piny ma pire tek. ma nyayu nyoth pa atomic man energy level nen i cal 1b man Supplementary Table 1. Ber pa lembe, epe nya peko ceke dwoko piny kero pa α-δ phase transition (cal 1b). Wayiyu niya peko ma tiye ku tego ma nok mi yik man tego ma nok mi α-δ phase transition energy barriers nen ni rac ni phase stability. Calu ma jukoro con, kabedo ma dwong ku lead nen ni ber pi formamidine PSC27. Pieno, wabe ketho wigi ikum PbI2-terminated (100) surface ithe lead-rich conditions. Teko mi yubu peko pa peko mi kabedo nen i cal mir 1c man Supplementary Table 1. Malube ku tego pa kero (EB) man teko mi loko rwom (FE), peko eni jupoko gi i dul adek. Kit I (low EB-high FE): Kadi bende IPb, VFA man VPb dwoko piny kero ma juketho pi loko rwom, gitiye ku kero madit mi yubu. Pieno, wayiyu niya kit peko eni utiye ku adwogi manok ikum aloka loka pa piny, kum gi bedo nok. Type II (high EB): Pi bero pa α-δ phase transition energy barrier, anti-site defects PbI, IFA man PbFA nyayu ngo peko i phase stability pa α-FAPbI3 perovskite. Type III (low EB-low FE): VI, Ii man Pbi defects ku relatively low formation energy copo kelo black phase degradation. Mapire tek ni FE man EB VI ma piny, wayiyu niya yore maber uloyu utiye mi dwoko piny I vacancies.
Mi jwigo VI, wayubu dul ma pek pa PbC2O4 mi medo rwom pa FAPbI3. Ka juporo ku organic halide salt passivators calu phenylethylammonium iodide (PEAI) man n-octylammonium iodide (OAI), PbC2O4, ma epe ku mobile halogen ions, utiye chemically stable, insoluble in water, man easy deactivated when stimulation. Bedo maber pa pii ma iwi ngom man teko pa perovskite. Solubility pa PbC2O4 i pii utiye 0.00065 g/L kende, ma utiye piny uloyu ma sagu pa PbSO428. Ma piretek uloyu, dul pa LOS ma gwai man ma rom rom jucopo yiko iwi perovskite films ni tiyo ku in situ reactions (nen piny). Watimo DFT simulations pa interfacial bonding ikind FAPbI3 ku PbC2O4 calu ma ju nyuthu i Supplementary Figure 1. Supplementary Table 2 nyuthu tego pa defect formation ingey LOS injection. Wanwango ni LOS medo kero pa VI kende ku 0.69-1.53 ​​eV (lanyut 1d), ento medo kero pa I i kabedo mi ngwec man kabedo mi wok woko (lanyut 1e). I rwom mir acel, I ions wotho iwi perovskite surface, weko VI ions i lattice position ku energy barrier pa 0.61 eV. I ngei kelo LOS, pi adwogi pa steric hindrance, kero mi tic pi wotho pa I ions umedire ni. 1.28 eV. I kare mi wotho pa I ions ma weko perovskite, kero ma juketho i VOC de utiye malo uloyu i sample ma jutiyo kudu (cal 1e). Cal pa I ion migration pathways in control man LOS FAPbI3 nen i cal mir acel f ku g, kubang wadi. Adwogi pa simulation nyutho nia LOS copo juku yik pa VI man volatilization pa I, man kumeno juku nucleation pa α ni δ phase transition.
Kit ma oxalic acid ku FAPbI3 perovskite timo kudo jutemo. I ngei rubu pa oxalic acid ku FAPbI3, wel madit pa pii ma tar ugam uwok, calu ma ju nyuthu i Supplementary Figure 2. Piny ma juyubu ubedo PbC2O4 maleng ni tiyo ku X-ray diffraction (XRD) (Supplementary Figure 3) man Fourier transform infrared spectroscopy (FT) (Supplementary Figure 4). Wanwango ni oxalic acid utiye ma nyai i isopropyl alcohol (IPA) i rwom ma piny pa ot ku nyai ma romo 18 mg/mL, calu ma ju nyuthu i Supplementary Figure 5. Eni miyo tic ma lubo doko yot nikum IPA, calu passivation solvent ma dhanu zo tiyo kudu, nyayu ngo peko i perovskite layer ingey kare manok. Pieno, ka jubolo perovskite film i oxalic acid solution nyo spin-coating oxalic acid solution iwi perovskite, PbC2O4 ma nyap man ma pek copo nwangire pio pio iwi perovskite film nimakere ku equation mi chemical ma e: H2C2O4 + FAPI3 = PbI3 + FAIO4 FAI copo bedu ma nyai i IPA man juwodhe woko ikare mi tedo. Pek pa LOS jucopo jwigo ku kare mi dwoko wang lembe man dwong pa piny ma kwong.
Scanning electron microscopy (SEM) cal pa control man LOS perovskite films nen i cal 2a,b. Adwogi ne nyutho nia kite ma perovskite nen kudu ubedo maber, man wel madwong pa jamb piny ma nyap ucungo iwi kodhi, ma ucikere ni nyuthu PbC2O4 layer ma juyubu ku in-situ reaction. LOS perovskite film utiye ku ngete ma yot nyanok (Cal mir 6) man rwom ma lac mi mako pii ka juporo ku film mi control (Cal mir 7). High-resolution transverse transmission electron microscopy (HR-TEM) jutiyo kudu pi poko kind piny ma jucul. Ka juporo ku filim ma jutiyo kudu (cal 2c), dul ma nyap man ma nyap ma lac pa 10 nm nen maleng iwi LOS perovskite (cal 2d). Ni tiyo ku high-angle annular dark-field scanning electron microscopy (HAADF-STEM) mi ngiyo interface ikind PbC2O4 ku FAPbI3, bedo pa crystalline regions pa FAPbI3 man amorphous regions pa PbC2O4 copo nen maleng (Supplementary Figure 8). Kit ma perovskite nen kudu ingey tic ku oxalic acid juporo ku X-ray photoelectron spectroscopy (XPS), calu ma ju nyuthu i cal 2e-g. I cal mir 2e, C 1s ucungo iwi 284.8 eV man 288.5 eV ubedo pa CC man FA signals, kubang wadi. Ka juporo ku membrane ma jugwoko, LOS membrane unyutho rwom ma malu pa 289.2 eV, ma juporo ku C2O42-. O 1s spectrum pa LOS perovskite nyutho O 1s adek ma tung tung i 531.7 eV, 532.5 eV, man 533.4 eV, ma rwate ku deprotonated COO, C=O pa intact oxalate groups 30 man O atoms pa OH component (Fig. 2). )). Pi lanyuth ma jutiyo kudu, O 1s ma nok kende re ma juneno, ma copo bedu ni oxygen ma jucwalo iwi ngom. Kite ma dul pa Pb 4f7/2 ku Pb 4f5/2 nen kudu utiye i 138.4 eV man 143.3 eV, kubang wadi. Waneno nia LOS perovskite nyutho aloka loka pa Pb peak ma romo 0.15 eV ni rwom ma malu mi mako, ma nyutho rwate matek ikind C2O42- ku Pb atoms (cal 2g).
a SEM cal pa control man b LOS perovskite films, nen malu. c High-resolution cross-sectional transmission electron microscopy (HR-TEM) pa control man d LOS perovskite films. XPS maber pa e C 1s, f O 1s man g Pb 4f perovskite films. Lembe ma wok kud i iye jumiyo i ayi pa lembe ma wok kud i iye.
Nimakere ku adwogi pa DFT, juporo nia VI defects man I migration copo kelo aloka loka pa α ni δ. Lapor mukadho unyutho nia I2 wok nyathotho kud i PC-based perovskite films i saa mi photoimmersion ingey ketho filim ne i lero man lyethu31,32,33. Mi ketho cing ikum tic pa lead oxalate ikum α-phase pa perovskite, wabolo control man LOS perovskite films i agulu ma nen maleng ma tye ku toluene, kubang wadi, man wa ketho gi ku lero pa ceng 1 pi sawa 24. Wapimo rwom pa ler ma nen (UV-Vis). ) toluene solution, calu ma ju nyuthu i cal mir 3a. Ka juporo ku lanyuth ma jutiyo kudu, I2 ma nok uloyu nenre i lembe pa LOS-perovskite, ma nyutho nia compact LOS copo juku wodhu pa I2 kud i perovskite film i saa mi lero. Cal pa aged control man LOS perovskite films junyutho gi insets pa cal 3b ku c. LOS perovskite podi ubedo macol, ma pol pa filim ma jutiyo kudu udoko makwar. UV-visible absorption spectra pa filim ma juketho i pii nen i cal. 3b, c. Waneno nia mako ma rwate ku α i filim ma jugwoko ubedo piny maleng. Pim pa X-ray jutimo pi ni goyo aloka loka pa kit ma crystal nen kudu. I ngei sawa 24 mi ler, perovskite ma jutiyo kudu unyutho δ-phase signal ma tek (11.8°), ma LOS perovskite podi unyutho rangi macol maber (lanyut 3d).
UV-visible absorption spectra of toluene solutions in which the control film and LOS film were immersed under 1 sunlight for 24 hours. Inset nyuthu vial ma i iye filim acel acel juyike i dwong pa toluene marom. b UV-Vis absorption spectra of control film and c LOS film before and after 24 h of immersion under 1 sunlight. Inset nyuthu cal pa filim mi temo. d X-ray diffraction patterns of control and LOS films before and after 24 h of exposure. Cal pa SEM pa filim e man filim f LOS ingey sawa 24 mi nyuthu. Lembe ma wok kud i iye jumiyo i ayi pa lembe ma wok kud i iye.
Watimo scanning electron microscopy (SEM) pi neno aloka loka pa microstructural pa perovskite film ingey sawa 24 mi ler, calu ma ju nyuthu i cal 3e,f. I filim mi tela, kodhi madongo unyothere man edoko sindo ma nok, ma rwate ku kit pa δ-phase product FAPbI3 (cal 3e). Pi filim pa LOS, kodhi pa perovskite bedo maber (lanyut 3f). Adwogi ne unyutho nia rweny pa I nyayu aloka loka kud i rangi macol ni rangi macol, ma PbC2O4 ketho rangi macol bedo maber, ma juku rweny pa I. Calu ma vacancy density iwi ngom utiye malo uloyu i wi lum,34 rwom eni copo timere iwi ngom pa lum. i saa marom weko iodine man timo VI. Calu ma DFT ukoro, LOS copo juku yik pa VI man juku wotho pa I ions ikum perovskite.
Mi medo, adwogi pa PbC2O4 layer ikum kero pa perovskite films i yamu mi polo (relative humidity 30-60%) jutimo sayusac iwie. Calu ma ju nyuthu i cal mir 9, LOS perovskite podi ubedo macol ingey nindu 12, ma control film udoko makwar. I pima pa XRD, filim ma jutiyo kudu nyuthu rwom ma malu i 11.8° ma rwate ku δ phase pa FAPbI3, ma LOS perovskite ugwoko α phase macol maber (Cal mir 10).
Steady-state photoluminescence (PL) man time-resolved photoluminescence (TRPL) jutiyo kudu pi ponjo tic pa lead oxalate iwi perovskite. I cal. cal mir 4a nyutho nia LOS film umedire ku tego pa PL. I cal pa PL, tego pa LOS film iwi ngom mi 10 × 10 μm2 utiye malo uloyu pa control film (Supplementary Figure 11), ma nyutho nia PbC2O4 timo perovskite film. Kwo pa carrier ungiyure ku rwom pa TRPL decay ku exponential function acel (cal 4b). Kwo pa LOS film ubedo 5.2 μs, ma ubedo bor uloyu ma sagu pa control film ku kwo pa 0.9 μs, ma nyutho nya dwoko piny pa nonradiative recombination.
PL ma rwinyo man b-spectra pa PL ma rwinyo pa perovskite films iwi glass substrates. c SP curve pa jam tic (FTO/TiO2/SnO2/perovskite/spiro-OMeTAD/Au). d EQE spectrum man Jsc EQE spectrum ma jukwanu kud i jam tic maber loyo. d Gen pa ler pa perovskite device ikum Voc diagram. f MKRC ma jutimo ku ITO/PEDOT:PSS/perovskite/PCBM/Au clean hole device. VTFL ubedo voltage ma malu pa pong pa trap. Kud i lembe eni wa kwanu pek pa trap (Nt). Lembe ma wok kud i iye jumiyo i ayi pa lembe ma wok kud i iye.
Pi niponjo adwogi pa lead oxalate layer ikum tic pa jam tic, jutiyo ku yore macon mi FTO/TiO2/SnO2/perovskite/spiro-OMeTAD/Au. Watiyo ku formamidine chloride (FACl) calu piny ma jumedo i perovskite precursor kakare pa methylamine hydrochloride (MACl) pi nwangu tic maber pa jam tic, pi FACl copo miyo crystal maber man jwigo band gap pa FAPbI335 (nen Supplementary Figures 1 ku 2 pi poro maber). ). 12-14). IPA juyeru ni antisolvent pi en emiyo rwom maber pa crystal man rwom maber in perovskite films ka juporo ku diethyl ether (DE) nyo chlorobenzene (CB)36 (Supplementary Figures 15 and 16). Pek pa PbC2O4 juyike maber pi rwom pa defect passivation man charge transport ku loko oxalic acid concentration (Supplementary Figure 17). Cal pa SEM ma juyubu maber man LOS ju nyuthu gi i cal mir 18. Kit ma rwom pa mac (CD) pi jam tic man LOS ju nyuthu gi i cal mir 4c, man lembe ma juwodho ju nyuthu i Supplementary Table 3. Maximum power conversion efficiency (PCE) cells controls (34%, 24%, 2924 J.C.). 25.75 mA cm-2 (25.74 mA cm-2), Voc 1.16 V (1.16 V) man reverse (forward) scan. The fill factor (FF) utiye 78.40% (76.69%). Maximum PCE LOS PSC utiye 25.39% (24.79%), Jsc utiye 25.77 mA cm-2, Voc utiye 1.18 V, FF utiye 83.50% (81.52%) kud i ngeye (i ngeye Scan to). Jam tic pa LOS unwangu tic maber pa mac ma romo 24.92% i ot yath ma juyio (Supplementary Figure 19). External quantum efficiency (EQE) umio Jsc ma 24.90 mA cm-2 (control) man 25.18 mA cm-2 (LOS PSC), kubang wadi, ma ubedu i winjiri maber ku Jsc ma jupimu i standard AM 1.5 G spectrum (Fig. .4d). ) . Poko pa PCEs ma jupimo pi control man LOS PSCs nen i Supplementary Figure 20.
Calu ma ju nyuthu i cal mir 4e, wat ma ni ikin Voc ku kero pa ler ju kwanu pi ni ponjo adwogi pa PbC2O4 ikum trap-assisted surface recombination. Kabedo pa line ma juketho pi jam tic pa LOS utiye 1.16 kBT/sq, ma utiye piny uloyu rwom pa line ma juketho pi jam tic mi tela (1.31 kBT/sq), ma nyutho nia LOS ber pi juku rwom pa piny ma juketho i iye ku decoys. Watiyo ku space charge current limiting (SCLC) technology mi pimo pek pa perovskite film ni pimo dark IV characteristic pa hole device (ITO/PEDOT:PSS/perovskite/spiro-OMeTAD/Au) calu ma ju nyuthu i cal. 4f Nyuth. Pek pa trap ju kwanu ku formula Nt = 2ε0εVTFL/eL2, kama ε utiye dielectric constant pa perovskite film, ε0 utiye dielectric constant pa vacuum, VTFL utiye limiting voltage pi pongu trap, e utiye charge, L utiye thickness pa perovskite film (60 nom). Pek pa peko pa jam tic pa VOC ju kwanu ni 1.450 × 1015 cm-3, ma piny pa pek pa peko pa jam tic mi tela, ma ubedo 1.795 × 1015 cm-3.
Jam tic ma jukwanu ngo ju temo i kabedo ma tek (MPP) i the lero pa ceng i the nitrogen pi nineno ka tic pare ubedo maber pi kare malac (lanyut 5a). I ngei sawa 550, LOS device podi utiye ku 92% pa tic pare maber, man tic pa control device udok piny ni 60% pa tic pare macon. Poko pa piny i jam tic macon jupimu ku time-of-flight secondary ion mass spectrometry (ToF-SIMS) (cal 5b, c). Iodine madwong copo nen in kabedo ma malu pa gold control. Kite ma inert gas protection uketho kudu piny ma nyayu peko i kabedu calu pii man oxygen, ma nyutho nia yore ma iye (niwacu, wotho pa ion) re ma nyayu peko. Nimakere ku adwogi pa ToF-SIMS, I- man AuI2- ions junwango i Au electrode, ma nyutho nyayu pa I kud i perovskite i Au. Teko pa lanyuth pa I- man AuI2- ions i jam tic ma jutiyo kudu pi gwoko piny ubedo 10 ma malu uloyu pa VOC. Lapor mukadho unyutho nia ion permeation copo nyayu dwoko piny pa hole conductivity pa spiro-OMeTAD man chemical corrosion pa electrode layer ma malu, ma copo nyayu rac pa interfacial contact i device37,38. Au electrode juwodho man spiro-OMeTAD layer juyike kud i substrate ku chlorobenzene solution. I ngeye wapoko filim ni tiyo ku grazing incidente X-ray diffraction (GIXRD) (lanyut 5d). Adwogi ne nyutho nia filim ma jugwoko utiye ku diffraction peak ma nen kamaleng i 11.8°, man diffraction peak manyen epe i LOS sample. Adwogi ne nyutho nia rweny madit pa I ions in control film ucwalu yik pa δ phase, man i LOS film timo eni jukwero.
575 sawa mi lubo MPP ma rwinyo pa jam tic ma juketho ngo i iye nitrogen man lero pa ceng 1 ma UV filter ope i iye. ToF-SIMS poko pa b I- man c AuI2- ions in LOS MPP control device man aging device. Rangi pa yellow, green man orange rwate ku Au, Spiro-OMeTAD man perovskite. d GIXRD pa perovskite film ingey MPP test. Lembe ma wok kud i iye jumiyo i ayi pa lembe ma wok kud i iye.
Temperature-dependent conductivity jupimu pi ketho cing ikum PbC2O4 copo juku ion migration (Supplementary Figure 21). Teko mi tic (Ea) pa ion migration ungiyure ku pimo aloka loka mi conductivity (σ) pa FAPbI3 film i temperature matung tung (T) man tic ku Nernst-Einstein relation: σT = σ0exp(−Ea/kBT), kama σ0 utiye piny ma rwinyo, kB utiye piny ma rwinyo Boltn. Wanwango wel pa Ea kud i rwom pa ln(σT) ku 1/T, ma en e 0.283 eV pi jam tic man 0.419 eV pi jam LOS.
I ayi ma kicoko, wabe mio yub mi nyang ikum yore mi nyoth pa FAPbI3 perovskite man adwogi pa peko matung tung ikum kero pa α-δ phase transition. Ikind peko eni, peko pa VI juporo ni kelo aloka loka pa α ni δ. Piny ma rwinyo ngo i pii man ma rwinyo ku kemikol pa PbC2O4 jukelo pi gwoko α-phase pa FAPbI3 ni juku yik pa I vacancies man wotho pa I ions. Yore eni dwoko piny rwom pa non-radiative recombination, medo kero pa solar cell ni 25.39%, man medo kero pa tic. Adwogi mwa umiyu telowic pi nwangu formamidine PSCs maber man ma ling ni juku loko pa α ni δ.
Titanium(IV) isopropoxide (TTIP, 99.999%) juwilu kud i Sigma-Aldrich. Hydrochloric acid (HCl, 35.0–37.0%) man ethanol (anhydrous) juwilu kud i Guangzhou Chemical Industry. SnO2 (15 wt% tin(IV) oxide colloidal dispersion) juwilo kud i Alfa Aesar. Lead(II) iodide (PbI2, 99.99%) juwilu kud i TCI Shanghai (China). Formamidine iodide (FAI, ≥99.5%), formamidine chloride (FACl, ≥99.5%), methylamine hydrochloride (MACl, ≥99.5%), 2,2′,7,7′-tetrakis-(N , N-di-p) )-methoxyaniline)-spir,9′-biofluore (Spiro-OMeTAD, ≥99.5%), lithium bis(trifluoromethane)sulfonylimide (Li-TFSI, 99.95%), 4-tert -butylpyridine (tBP, 96%) juwilo kud i Xi'an Polymer Light Technology Company (China). N,N-dimethylformamide (DMF, 99.8%), dimethyl sulfoxide (DMSO, 99.9%), isopropyl alcohol (IPA, 99.8%), chlorobenzene (CB, 99.8%), acetonitrile (ACN). Juwilu kud i Sigma-Aldrich. Oxalic acid (H2C2O4, 99.9%) juwilu kud i bang Macklin. Kemikol zo jutiyu kudu kite ma junwango kudu labongo aloka loka moku cii.
ITO nyo FTO substrates (1.5 × 1.5 cm2) juyike ku ultrasonically ku detergent, acetone, man ethanol pi dakika 10, kubang acel acel, man juyike i the nitrogen stream. TiO2 ma tek juyike iwi FTO substrate ku tiyo ku titanium diisopropoxybis(acetylacetonate) in ethanol (1/25, v/v) majuketho i 500 °C pi dakika 60. SnO2 colloidal dispersion juyike ku pii ma deionized i ratio pa 1:5. I wi piny maleng ma jutiyo kudu ku UV ozone pi dakika 20, juyiko filim ma nyap pa SnO2 nanoparticles i 4000 rpm pi sekond 30 man juyike i 150 °C pi dakika 30. Pi perovskite precursor solution, 275.2 mg FAI, 737.6 mg PbI2 man FACl (20 mol%) juyike i DMF/DMSO (15/1) mixed solvent. The perovskite layer juyike ku centrifuging 40 μL pa perovskite precursor solution iwi UV-ozone-treated SnO2 layer i 5000 rpm i yamo pi 25 s. 5 seconds ingey kare mir ajiki, 50 μL pa MACl IPA solution (4 mg/mL) jubolo pio pio iwi substrate calu antisolvent. I ngeye, filim ma juyubu manyen juyike i 150°C pi dakika 20 man i 100°C pi dakika 10. I ngei jwigo perovskite film ni piny ma ngic, H2C2O4 solution (1, 2, 4 mg dissolved in 1 mL IPA) ju centrifuged i 4000 rpm pi 30 s mi juku perovskite surface. Piny ma juyiko ku spiro-OMeTAD ma juyiko ku rubu 72.3 mg spiro-OMeTAD, 1 ml CB, 27 μl tBP man 17.5 μl Li-TFSI (520 mg in 1 ml acetonitrile) juyiko iwi filim i 4000 rpm i kind 300 s. I ajiki, 100 nm thick Au layer ubedo evaporated i vacuum ku rwom pa 0.05 nm/s (0~1 nm), 0.1 nm/s (2~15 nm) man 0.5 nm/s (16~100 nm) . ).
Tic pa SC pa perovskite solar cells jupimu ku tic ku Keithley 2400 meter under solar simulator illumination (SS-X50) ku mac ma tek pa 100 mW/cm2 man juporo ku calibrated standard silicon solar cells. Ka jukwanu ngo lembe mange, SP curves jupimu i nitrogen-filled glove box i room temperature (~25°C) i forward man reverse scan modes (voltage step 20 mV, delay time 10 ms). Shadow mask jutiyo kudu pi nyang kabedo maber pa 0.067 cm2 pi PSC ma jupimu. Pim pa EQE jutimo i yamu ma iye ku tic ku PVE300-IVT210 system (Industrial Vision Technology(s) Pte Ltd) ku ler ma rangi acel kende ma juketho iwi jam tic. Pi bedo maber pa jam tic, temo pa non-encapsulated solar cells jutimo i nitrogen glovebox i 100 mW/cm2 pressure manangu UV filter epe. ToF-SIMS jupimu ku PHI nanoTOFII time-of-flight SIMS. Nyuthu rwom pa piny ju nwango ku tic ku 4 kV Ar ion gun ku kabedu pa 400×400 μm.
Pim pa X-ray photoelectron spectroscopy (XPS) jutimo iwi Thermo-VG Scientific system (ESCALAB 250) ma jutiyo kudu ku monochromatized Al Kα (pi XPS mode) i pressure pa 5.0 × 10–7 Pa. Scanning electron microscopy (SEM) jutimo iwi JESM-JOL-JOL-630 F system. Kite ma piny nen kudu man tek pa perovskite films jupimu ku tic pa atomic force microscopy (AFM) (Bruker Dimension FastScan). STEM man HAADF-STEM jutimo i FEI Titan Themis STEM. UV-Vis absorption spectra jupimu ku UV-3600Plus (Shimadzu Corporation). Space charge limiting current (SCLC) ju goyo iwi Keithley 2400 meter. Steady-state photoluminescence (PL) man time-resolved photoluminescence (TRPL) pa carrier lifetime decay jupimu ku tic ku FLS 1000 photoluminescence spectrometer. PL mapping images jupimu ku tiyo ku Horiba LabRam Raman system HR Evolution. Fourier transform infrared spectroscopy (FTIR) jutimo ku kony pa Thermo-Fisher Nicolet NXR 9650 system.
I tic maeni, watiyo ku yore mi SSW path sampling pi niponjo yore mi loko pa phase kud i α-phase ni δ-phase. I yore mi SSW, wotho pa piny ma copo bedu ku tego ucungo iwi yo pa random soft mode (derivative mir aryo), ma weko jutimo somo matuc man ma rwinyo pa piny ma copo bedu ku tego. I tic eni, timo sampling pa 72-atom supercell, man 100 ma kadhu 100 mi acaki/ajiki (IS/FS) pairs jucoko i DFT level. Malube ku IS/FS pairwise data set, yo ma mako kit ma acaki ku kit ma tok cen jucopo nwangu ku rwate pa atoms, man i ngeye wotho pa yore aryo iwi ngom ma tung tung jutiyo kudu pi nyang yore mi loko. (VK-DESV). I ngei sayu lembe mi loko, yo ma rwom pare piny uloyu jucopo nwangu ku rwom pa rwom pa kero.
Kwan pa DFT zo jutimo ku VASP (version 5.3.5), kama electron-ion interactions pa C, N, H, Pb, man I atoms ju nyuthu ku projected amplified wave (PAW) scheme. Tic mi rwate pa wil jukoro ku rwom pa gradient ma rwate in Perdue-Burke-Ernzerhoff parametrization. Kabedo pa kero pa yamo ma mol iwi polo juyike ni 400 eV. Monkhorst-Pack k-point grid utiye ku dit pa (2 × 2 × 1). Pi gedo zo, lattice man atomic positions juyike maber nitundu ma stress component ubedo piny 0.1 GPa man maximum force component ubedo piny 0.02 eV/Å. I lanyuth pa wi ngom, wi ngom pa FAPbI3 utiye ku dul angwen, dul ma piny utiye ku atom ma ucungo ma calu kum pa FAPbI3, man dul adek ma malu copo wotho agonya i kare mi yubu piny. PbC2O4 layer utiye 1 ML man utiye iwi I-terminal surface pa FAPbI3, kama Pb utiye ku 1 I man 4 O.
Pi ningeyo lembe mukende ikum yub mi somo, nen Natural Portfolio Report Abstract ma rwate ku lembe eni.
Lembe ceke ma junwango nyo majutimo i saa mi somo eni juketho i lembe ma jugoro, man bende i lembe ma jukonyo man i fail pa lembe ma jugoro. Lembe ma jukwanu i somo eni nwangre i https://doi.org/10.6084/m9.figshare.2410016440. Lembe ma wok kud i iye jumiyo pi kyeu eni.
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