Challenges and Perspectives toward Future Wide‐Bandgap Mixed‐Halide Perovskite Photovoltaics

Abstract

Wide‐bandgap (WBG) perovskite solar cells (PSCs) are acknowledged as promising candidates for multijunction tandem and building photovoltaics, which attract broad research interest in related research communities. However, the performance of WBG PSCs based on the mixed‐halide perovskites still lags far behind their pure‐iodide counterparts because of the complex compositional evolution, huge photovoltage deficits, and intrinsic spectral losses. Here, by comprehensively understanding the representative WBG PSCs, the main “WBG drawbacks” from the device point of view are discussed in‐depth and three intrinsic critical issues for the growth of high‐quality WBG perovskites are proposed. The prospects for WBG PSCs toward future advancements and commercialization are also presented to guide the coming research hot spots.

Efficient Semi-Transparent Wide-Bandgap Perovskite Solar Cells Enabled by Pure-Chloride 2D-Perovskite Passivation

“…At present, increasing the bromide content in the X site is a common strategy for preparing WBG perovskite. So WBG perovskite will face more unique challenges than the narrow-bandgap perovskite, such as smaller grains, more grain boundaries, and more serious photo-induced phase segregation [ 20 ]. Moreover, the energy levels of WBG perovskite may mismatch with the carrier transport layer that is commonly used in high-efficient narrow-bandgap devices.…”

Surface Passivation Suppresses Local Ion Motion in Halide Perovskites

“…33−35 We focus our study on wide-gap (∼1.7 eV), mixed halide perovskites because such formulations are particularly relevant for perovskite-on-silicon tandem photovoltaics and because ion migration often causes halide phase segregation in these compositions. 25,36 We find that the contact potential difference (CPD) of the perovskite samples evolves with the applied electric fields. We quantify the average shift in CPD for perovskite control films to be near ∼100 mV at poling extremes of ±3 V with a dwell time of only a few seconds, which is reduced to ∼20 mV after surface passivation with APTMS.…”

“…We combine SKPM measurements on locally poled perovskite samples with studies of photoluminescence using hyperspectral photoluminescence microscopy. The use of SKPM allows us to probe ion motion and effects of APTMS surface passivation below the optical diffraction limit of conventional photoluminescence measurements. − We focus our study on wide-gap (∼1.7 eV), mixed halide perovskites because such formulations are particularly relevant for perovskite-on-silicon tandem photovoltaics and because ion migration often causes halide phase segregation in these compositions. , We find that the contact potential difference (CPD) of the perovskite samples evolves with the applied electric fields. We quantify the average shift in CPD for perovskite control films to be near ∼100 mV at poling extremes of ±3 V with a dwell time of only a few seconds, which is reduced to ∼20 mV after surface passivation with APTMS.…”

Effects of Solvent Vapor Atmosphere on Photovoltaic Performance of Perovskite Solar Cells

“…All the commercial materials were used as received without further purification, including ethanol (AR Beijing Chemical Works, Beijing, China), chlorobenzene (99.9%, Sigma-Aldrich, St. Louis, MO, USA), isopropanol (IPA, 99.99%, Sigma-Aldrich, St. Louis, MO, USA), N,N-dimethylformamide (DMF, 99.99%, Sigma-Aldrich, St. Louis, MO, USA), Dimethyl sulfoxide (DMSO, 99.9%, Sigma-Aldrich, St. Louis, MO, USA), Toluene (TL, 99.98%, Sigma-Aldrich, St. Louis, MO, USA), Poly (triarylamine) (PTAA, Xi'an Polymer Light Technology Corp., Xi'an, China), [6,6]-Phenyl C 61 butyric acid methyl ester (PC 61 BM, Xi'an Polymer Light Technology Corp., Xi'an, China), PbI 2 (99.999%, Xi'an Polymer Light Technology Corp., Xi'an, China), CsI (99.90%, Sigma-Aldrich, St. Louis, MO, USA), Formamidinium iodide (FAI, Xi'an Polymer Light Technology Corp., Xi'an, China).…”

“…Perovskite solar cells (PSCs) have been recognized as one of the most promising candidates for the next generation of photovoltaics (PV). Benefiting from distinguished advantages [2][3][4][5], including low exciton binding energy, high defect tolerance and long diffusion length, the power conversion efficiency (PCE) of PSCs has reached 25.7% within decades, rivaling already the conventional silicon (Si) cells (~26.7%) [6].…”