Self‐Assembled 1D/3D Perovskite Heterostructure for Stable All‐Air‐Processed Perovskite Solar Cells with Improved Open‐Circuit Voltage

Abstract

Environmental instability and photovoltage loss induced by defects are inevitable obstacles in the development of all-airprocessed perovskite solar cells (PSCs). In this study, the ionic liquid 1-ethyl-3-methylimidazolium iodide ([EMIM]I) is introduced into the hole transport layer/three-dimensional (3D) perovskite interface to form a self-assembled 1D/3D perovskite heterostructure, which significantly reduces iodine vacancy defects and modulates band energy alignment, resulting in pronouncedly improved open-circuit voltage (V oc ). As a result, the corresponding device exhibits a high power conversion efficiency with negligible hysteresis and a high V oc of 1.14 V. Most importantly, together with the high stability of the 1D perovskite, remarkable high environmental and thermal stabilities of the 1D/3D PSC devices are achieved, which maintain 89 % of unencapsulated device initial efficiency after 1320 h in air and retain 85 % of the initial efficiency when heated at 85 °C for 22 h. This study affords an effective strategy to fabricate high-performance all-air-processed PSCs with outstanding stability.

Buried interface modification by multifunctional ionic liquids for triple-cation perovskite solar cells made in a fully ambient air

“…Electrochemical impedance spectroscopy (EIS) was conducted to investigate the charge transfer behaviors in PSCs under dark conditions. 33 As depicted in Fig. 5b and Table S4 (ESI†), the starting point of the EIS curves can be assigned to the series resistance ( R s ), which is the resistance of the FTO, interface, and wire.…”

“…In recent years, the fabrication process of PSCs in ambient air without a strictly controlled environment has gained great attention owing to the simplified manufacturing process and low cost. 31–37 Nevertheless, overcoming the low intrinsic stability of all-air-processed PSCs is essential. The Cs-containing mixed cation perovskite is considered as one of the most effective solutions to address the stability issue.…”

Long-chain organic molecules enable mixed dimensional perovskite photovoltaics: a brief view

“…The final device achieved a certified record PCE of 18.05% for HTM-free inorganic C-PSCs. Meng et al (2023) introduced the ionic liquid 1-ethyl-3-methylimidazolium iodide ([EMIM]I) to the 3D perovskite surface, reducing iodine vacancy defects and modulates band energy alignment, resulting in a substantial enhancement of the open circuit voltage ( V oc ) ( Figure 3E ). Consequently, the device achieves a high PCE and remarkable environmental and thermal stability.…”