Acidity Control of Interface for Improving Stability of All‐Perovskite Tandem Solar Cells

Abstract

Developing all‐perovskite tandem solar cells has been proved to be an effective approach to boost the efficiency beyond the Shockley–Queisser limit. However, the Sn‐based narrow‐bandgap (NBG) perovskite solar cells (PSCs) suffer from the relatively low photostability, which limits their further application in all‐perovskite tandem solar cells. In this work, the instability of NBG PSCs is found to come from the commonly used acidic hole transporting material PEDOT:PSS, which reacts with the indispensable basic additive SnF2 in the perovskite layer. By acidity control of PEDOT:PSS via aqueous ammonia, the NBG PSCs yield an efficiency of 22.0% with much improved photostability, which can maintain 91.3% of the initial value after 800 h illumination under AM 1.5G. As an application, the corresponding all‐perovskite tandem cells exhibit a stabilized efficiency of 25.3% with 92% remaining after 560 h illumination. This work reveals an origin of instability of NBG PSCs and provides an effective approach to enhance the device stability, which can promote the development of all‐perovskite tandem solar cells.

Tin–lead halide perovskite solar cells with a robust hole transport layer

“…This is probably caused by two factors, lower crystallinity of the perovskite film which may accelerate moisture intrusion and oxidation degradation, 30 and the acidic PEDOT : PSS induced erosion reaction. 28 We then raised the storage temperature to 85 °C to evaluate the thermal stability. Compared to the control, CC and CCST devices exhibited superior thermal stability, both retaining 88% of their initial PCE after 500 hours aging (Fig.…”

Surface Crystallization Enhancement and Defect Passivation for Efficiency and Stability Enhancement of Inverted Wide-Bandgap Perovskite Solar Cells

“…3−5 WBG PSC is currently the most efficient subcomponent among all tandem devices. 6,7 Yu et al have chosen perovskite with 1.67 eV bandgap to prepare the absorber layer of the top cell; the highest PCE of the fabricated tandem device is 28.35%, and the open-circuit voltage (V oc ) of the top cell is 1.21 V. 8 To prepare efficient perovskite stacked devices, efforts need to be made from the following two aspects. First, in theory, when the current of PSC is matched with that of the substrate silicon solar cell, for the larger bandgap perovskite, the greater V oc can be obtained; thus, the most efficient stacked device can be fabricated.…”

“…The recorded power conversion efficiency (PCE) of a regular and inverted single-junction perovskite solar cell (PSC) has been certified as 26.1%. , However, the tandem solar cell has been thought of as the effective way to solve the Shockley–Queisser limit. At present, the PCE can be further improved by using a wide-bandgap (WBG) solar cell as the top cell in a tandem solar cell with narrow-bandgap monocrystalline silicon (C–Si), copper indium gallium selenium (CIGS), or organic solar cells. − WBG PSC is currently the most efficient subcomponent among all tandem devices. , Yu et al have chosen perovskite with 1.67 eV bandgap to prepare the absorber layer of the top cell; the highest PCE of the fabricated tandem device is 28.35%, and the open-circuit voltage ( V oc ) of the top cell is 1.21 V …”

Efficient All‐Perovskite Tandem Solar Cells with Low‐Optical‐Loss Carbazolyl Interconnecting Layers

“…Poly(3,4‐ethylenedioxythiophene) polystyrenesulfonate (PEDOT : PSS), the most widely used hole transport layer (HTL) for mixed Pb‐Sn NBG perovskite solar cells (PSCs), functions as a crucial part of ICLs in all‐perovskite tandem solar cells; unfortunately, it brings about strong parasitic absorption losses in the near‐infrared spectral range (Figure S1, Supporting Information) [12–16] . Furthermore, PEDOT:PSS induces severe thermal instability and reacts adversely with mixed Pb‐Sn perovskites under elevated temperatures (i.e., at 85 °C), resulting in worsened charge extraction and degraded photovoltaic performance [17,18] . The reliance upon PEDOT : PSS currently hinders the further development of efficient and stable all‐perovskite tandem solar cells.…”