Metal halide perovskites are emerging as a new class of photoactive materials for next‐generation optoelectronics in recent years due to their unique optical and electronic properties. Regardless of significant progress on high‐performance perovskite‐based devices, it is of paramount importance to unveiling the interface energetics, which are crucial for the photon‐harvesting process and energy loss in the layered device configuration. In addition, the stability issue of perovskite materials and related devices has severely hindered their practical application. Herein, the recent advances in the interrelation between perovskite composition, electronic structure, and stability are reviewed. The interface energetics and band alignment with adjacent transport layers, as well as deterioration mechanisms, are addressed in terms of internal composition and external environmental factors. The strategies to improve the device efficiency and durability with interface modification are also discussed. The comprehensive microscopic understandings and precise control of electronic structures and degradation pathways exhibit great potential toward higher‐performance perovskite‐based optoelectronic devices.
Inorganic mixed‐halide CsPbX3‐based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic–inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol–gel‐derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs2CO3. Compared to bare ZnO, Cs2CO3‐doped ZnO possesses more favorable interface energetics in contact with the CsPbI2Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open‐circuit voltage of 1.28 V, together with an increase in fill factor and short‐circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs2CO3‐doped ZnO/CsPbI2Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C.
Excess
lead iodide (PbI2) plays a crucial role in passivating
the defects of perovskite films and boosting the power conversion
efficiency (PCE) of perovskite solar cells (PSCs). However, the photolysis
of PbI2 is easily triggered by light illumination, which
accelerates the decomposition of perovskite materials and weakens
the long-term stability of PSCs. Herein, the high light tolerance
of lead iodide (PbI2) is reported by introducing an electron-donor
molecule, namely, 2-thiophenecarboxamide (2-TCAm), to strengthen the
[PbX6]4– frame. Characterization reveals
that the retarded decomposition of PbI2 is attributed to
the interactions between Pb2+ and the organic functional
groups in 2-TCAm as well as the optimized distribution of PbI2. The crystallization and morphology of 2-TCAm-doped perovskite
films are improved simultaneously. The 2-TCAm-based PSCs achieve a
16.8% increase in PCE and nearly 12 times increase in the lifetime
as compared to the reference device. The demonstrated method provides
insight into the stability of PbI2 and its influence on
PSCs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.