Perovskite‐Compatible Carbon Electrode Improving the Efficiency and Stability of CsPbI₂Br Solar Cells

Abstract

Carbon electrodes are a promising alternative to metal electrodes in the access of high‐stable and low‐cost perovskite solar cells (PSCs). However, polar components (including cyclohexanone, terpineol, etc.) in commercial carbon pastes for carbon electrodes usually corrode perovskite materials, thereby deteriorating the photovoltaic performance of the resulting solar cells. Therefore, the development of perovskite‐compatible carbon pastes and carbon electrodes is of great significance in obtaining high‐performance carbon‐based PSCs. Herein, carbon pastes based on low polar alkane solvents are developed for perovskite‐compatible carbon electrode (PCCE) in the construction of carbon‐based CsPbI2Br PSCs. The optimized cells based on PCCE offer a champion efficiency of 13.16% (JSC = 14.33 mA cm−2, VOC = 1.22 V, and fill factor (FF) = 0.75), which is remarkably higher than that of commercial carbon paste‐derived counterparts (11.51%). Even without encapsulation, CsPbI2Br PSCs based on PCCE maintain over 93% of their initial efficiency in an air atmosphere with a humidity of 30–40% for over 1000 h.

Modification of Energy Level Alignment for Boosting Carbon‐Based CsPbI2Br Solar Cells with 14% Certified Efficiency

“…The small TPV/TPC signals were triggered by an attenuated laser pulse (532 nm, 1.344 ns) under equivalent open‐circuit/short‐circuit conditions. [ 7b,15,28 ] As shown in Figure 4e, the recombination lifetime of modified cells was 11.8 µs, which was much higher than that of pristine cells (6.4 µs), indicating that HTAB modification can effectively suppress the carrier recombination. In addition, the modified cells displayed a smaller charge extraction time (0.70 µs) (Figure 4f) than the pristine cells (1.29 µs), revealing an accelerated charge separation due to the higher V bi , as described in the Mott‐Schottky measurement.…”

“…film), wherein all experimental variables for the preparation of perovskite films have been optimized. [ 15 ] Herein, the flowing hot air and high‐temperature annealing process can provide an atmosphere with much lower relative humidity in comparison with the natural environment, therefore diminishing deleterious effects of moisture on perovskite. The detailed procedure for the perovskite film preparation is described in the Experimental Section in the Supporting Information.…”

“…[ 13a,24 ] CsPbI 3 has a small bandgap (≈1.7 eV), but its crystalline phase instability makes defect management difficult, especially in the assembly of C‐PSCs. [ 2a,15 ] In contrast, mixed halide CsPbI 2 Br possesses a balance between bandgap (≈1.9 eV) and phase stability, which makes CsPbI 2 Br C‐PSCs exhibit better photovoltaic performance than the other inorganic perovskite counterparts. To the best of our knowledge, this champion PCE of 14.3% and certified efficiency of 14.0% obtained in this work is a new efficiency record for carbon‐based inorganic PSCs.…”

S8 Additive Enables CsPbI2Br Perovskite with Reduced Defects and Improved Hydrophobicity for Inverted Solar Cells

“…Indium tin oxide (ITO) glass sheets with sheet resistance of 15 Ω sq −1 were cleaned subsequently using water, EtOH, acetone, and treated with UV–ozone cleaner for 15 min. [ 26 ] To prepare NiO x hole transporting layer (HTL), an EtOH solution of Ni(OCOCH 3 ) 2 ·4H 2 O (0.1 mol mL −1 ) containing 0.6 vol% diethanol amine was spin‐coated on an ITO substrate, followed by thermal annealing at 325 °C for 1 h. Perovskite precursor (1.2 m) was prepared by CsI (312 mg, 1.2 mmol), PbI 2 (277 mg, 1.2 mmol), and PbBr 2 (220 mg, 1.2 mmol) in 1 mL DMSO and stirred at 60 °C overnight. A DMSO solution containing 1 mg mL −1 S 8 was prepared in advance and added to perovskite precusor solution in proportion.…”

“…To date, intensive efforts have been devoted to developing the strategies for preparing high‐quality inorganic perovskite film. [ 24–27 ] Among various strategies, additive engineering has been of specific interest and well developed for ease of operation. [ 19,28–33 ] Nevertheless, different perovskites clearly require different regulations.…”