Dual Additive for Simultaneous Improvement of Photovoltaic Performance and Stability of Perovskite Solar Cell

Abstract

Additive engineering is one of the most efficient approaches to improve not only photovoltaic performance but also phase stability of formamidinium (FA)‐based perovskite. Chlorine‐based additives, such as methylammonium chloride (MACl), have been in general used to improve phase stability of FAPbI3, which however often leads to loss of open‐circuit voltage Voc, accompanied by instability of the perovskite phase due to the volatile nature of the MA cation. A dual additive strategy for improving Voc and thereby the overall efficiency are reported here. The mixing ratio of MACl to CsCl is varied from [MACl]/[CsCl] = 4 to 1, where Voc increases with decreasing the ratio and best performance is achieved from [MACl]/[CsCl] = 2. As compared to the single source of MACl, the addition of CsCl reduces trap density and increases resistance against charge recombination, which is responsible for the increased Voc. Moreover, defect passivation achieved by dual additive enables better stability than the single additive MACl as confirmed by long‐term stability tests with unencapsulated devices for 50 days under relative humidity of about 40% at room temperature. The best power conversion efficiency of 23.22% is achieved by dual additive, which is higher than that for single additive of MACl or CsCl.

Concentrated perovskite photovoltaics enable minimization of energy loss below 0.5 eV under artificial light‐emitting diode illumination

“…The PCE of phenethylammonium bromide‐treated perovskite (PEABr) was enhanced to 35.8% with an increased V OC of 0.94 V and J SC of 178 uA cm −2 compared to bare MAFA devices (PCE = 33.9%, V OC = 0.93 V, J SC = 171 uA cm −2 ). The reduced trap density after the optimization of the perovskite layer was investigated using space‐charge‐limited‐current (SCLC) measurement 29 using hole‐only perovskite devices (ITO/poly(3,4‐ethylenedioxy‐thiophene):poly(styrenesulfonate) (PEDOT:PSS)/perovskite/Spiro‐OMeTAD/Au), as depicted in Figure 2D. When the trap densities of devices were extracted from the trap‐filled limit voltage ( V TFL ), PEABr was observed to afford a highly reduced trap density of 5.36 × 10 15 cm −2 compared to the MA (8.23 × 10 15 cm −2 ) and MAFA without the surface treatment (5.95 × 10 15 cm −2 ).…”

Crystallization kinetics modulation and defect suppression of all-inorganic CsPbX3 perovskite films

“…3d). [131][132][133] The time-dependent carrier population neglecting the diffusion effect can be given by eqn (5), where k 1 , k 2 , and k 3 are the rate constants that represent defect-assisted (monomolecular), radiative (bimolecular) and Auger (three-body) recombination processes, respectively. n is the photo-generated carrier density.…”

“…In recent years, organic-inorganic hybrid perovskite solar cells (PSCs) have attracted tremendous attention owing to their impressive photovoltaic performance. [1][2][3][4][5][6] To date, they have achieved a certified champion power conversion efficiency (PCE) of greater than 25%, outperforming copper indium gallium selenide (CIGS) (PCE = 23.4%), CdTe (PCE = 22.1%), and multicrystalline Si (PCE = 22.8%) solar cells. 7 The perovskite materials are highly favorable for optoelectronic applications due to their exceptional optoelectronic properties such as the superior long carrier diffusion length and high optical absorption coefficient.…”

Efficient and Stable FA‐Rich Perovskite Photovoltaics: From Material Properties to Device Optimization

“…2021 [27] FAPbI 3 23.9 2D/3D _ _ _ _ 2021 [28] FAPbI 3 20.94 Additive Unencapsulated cells aged at 50 °C in N 2 for 1628 h, drop by ≈10% _ _ _ 2021 [29] Cs 0.05 FA 0.95 PbI 3 21.5 (Certified) 2D/3D _ _ Unencapsulated cells stored in the air of 35% RH for 400 h, drop by ≈19%…”

“…[135] Even though the CsCl additive is more stable than the MACl one, its photovoltaic overall performance is inferior to MACl. For this reason, Park et al [27] adopted a dual additive (MACl/CsCl) approach to simultaneously enhance the photovoltaic performance and stability of FA-rich PSCs. Pham et al [33] systematically studied the roles of the CsCl/MACl additives on the microstructure, crystal structure of nano twin, and stacking fault defects of FAPbI 3 perovskite.…”