Pushing the Limit of Open‐Circuit Voltage Deficit via Modifying Buried Interface in CsPbI₃ Perovskite Solar Cells

Abstract

harmful phase separation behavior, which makes it the most prominent candidate for high-efficiency single-junction cells or sub-cell absorbers in tandem cells. [1,2] It has witnessed tremendous progress in inorganic CsPbI 3 -based perovskite solar cells (PSCs) under unremitting efforts over the past few years, especially on stabilizing photo-active black phase and improving perovskite crystal quality. [3][4][5] However, the power conversion efficiency (PCE) of CsPbI 3 -based PSCs still remains inferior to that of organic-inorganic hybrid PSCs, primarily due to the serious photovoltage loss triggered by nonradiative charge carrier recombination. [5][6][7] Suffering from severe photovoltage loss, the open-circuit voltage (V OC ) reaches only 80% of the Shockley-Queisser (S-Q) theoretical limit, critically impeding further advancements in performance. [8][9][10] In this regard, reducing the V OC deficit is of great significance for promoting the efficiency of CsPbI 3 -based photovoltaics.Several approaches including additivesassisted crystallization techniques, post-treatment strategies, and antisolvent engineering methods have been developed to suppress the V OC deficit in CsPbI 3 -based solar cells. [11] Thereinto, additives engineering such as introducing inorganic ammonium halides, alien elements, and molten salts into the precursor solution has been proven to be an effective means through manipulating crystallization growth and enhancing perovskite crystallinity. [1,3,12] Alternatively, post-treatment on perovskite surfaces with 2D materials or methylammonium chloride has seen aroused interest to demonstrate some advantages in reducing V OC loss. [8,13] Moreover, employing solvent molecular sieves in the antisolvent induced rapid nucleation and slow crystal growth of CsPbI 3 films, thereby diminishing energy loss in photovoltaic devices. [5] Nevertheless, most strategies concentrated on the bulk or the top surfaces of CsPbI 3 perovskite. Little attention has been paid to tackling the bottleneck issues of the buried interface under CsPbI 3 perovskite thin films, resulting in a huge room to restrain the V OC deficit.Generally, the perovskite layer is clamped by the atop hole electron layer (HTL) and the bottom titanium oxide (TiO 2 ) electron transport layer (ETL) in a typical regular CsPbI 3 -based PSCs structure. The buried interface between TiO 2 ETL and perovskite possesses higher concentrations of imperfections than that of Although CsPbI 3 perovskites have shown tremendous potential in the photovoltaic field owing to their excellent thermal stability, the device performance is seriously restricted by severe photovoltage loss. The buried titanium oxide/perovskite interface plays a critical role in interfacial charge transport and perovskite crystallization, which is closely related to open-circuit voltage deficit stemming from nonradiative recombination. Herein, target molecules named 3-sulphonatopropyl acrylate potassium salts are deliberately employed with special functional groups for modifying the buried...

Interface Modification for Efficient and Stable Inverted Inorganic Perovskite Solar Cells

“…Since the short-circuit current (J SC ) of inorganic PSCs has almost approached its S-Q limit by tuning the composition [37][38][39] and processing methods [34,40,41,42] of the perovskite film, interfacial modification has become considerably necessary to ensure further advances in device performance, including open-circuit voltage (V OC ), fill factor (FF), hysteresis, and stability/reliability. It is because the interface is closely correlated with surface defects, energy level alignment and environmental contact.…”

“…It is because the interface is closely correlated with surface defects, energy level alignment and environmental contact. [43][44][45] Zhu et al reported that the oxidized Ti 3 C 2 T x MXene (OMXene) nanoplates on CsPbI 3 film can provide a physical barrier against moisture and improve charge separation at the perovskite-electron-transport layer (ETL) interface via an enhanced electric field. Consequently, CsPbI 3 /OMXene-based inverted devices demonstrated a 19.69% PCE.…”

Open-circuit voltage loss in perovskite quantum dot solar cells

“…Although several strategies and efforts have been made to optimize the fabrication of PQDs, there is still room to reduce the voltage loss in 1. [2][3][4][70][71][72][73][74][75][76] PQDSCs based on the whole device level. In Fig.…”

“…Schematic illustration of (b) voltage loss with respect to the bandgap for bulk PSCs and (c) voltage loss with respect to bandgap for PQDSCs. The plots are based on the data listed in Table1 [2][3][4][70][71][72][73][74][75][76].…”

Reduction-Active Antisolvent: A Universal and Innovative Strategy of Further Ameliorating Additive Optimization for High Efficiency Perovskite Solar Cells

“…Among the aforementioned methodologies, additive engineering is considered the most effective and promising option because of the well-established intrinsic coordination ability of lead cations in the [PbI 6 ] 4– octahedral matrix of perovskites. The unique polar characteristics of lead cations allow them to function as Lewis acids that can undergo coordinative bonding with numerous types of dopant molecular bases and perovskites. − Thus, a large diversity of additives and their functions, ranging from small molecules to polymers, can be exploited in improving the properties of perovskite films. Song et al proposed incorporating a poly­(styrene- co -butadiene) (SBS)-polyurethane (PU) composite into perovskites to facilitate crystal-orientated growth, thereby achieving excellent bending and stretching stability in related devices.…”