Enhanced Efficiency and Stability of Carbon‐Based Perovskite Solar Cells by Eva Interface Engineering

Abstract

Nanocrystalline tin (IV) oxide (SnO2) as an electron‐transport layer (ETL) has unique advantages in realizing highly efficient and stable planar perovskite solar cells (PSCs), especially showing great potential in the low‐temperature preparation of large‐area flexible carbon‐based PSCs (C‐PSCs). However, the high trap density on the surface of SnO2 tends to cause serious nonradiative recombination losses, thereby reducing photoelectric performance. In this work, an inexpensive and easily obtained polymer poly(ethylene‐co‐vinyl acetate) (Eva) is used as a interfacial modifier to reduce the interfacial defects and nonradiative recombination losses at the SnO2/perovskite interface. As a result, the crystallinity and conductivity of the perovskite layer are significantly increased, and the charge lifetime and stability are effectively improved. The Eva modified SnO2‐based C‐PSCs obtain an optimal power conversion efficiency (PCE) of 12.29%, which is 25.7% higher than that of 9.78% for the unmodified C‐PSCs. Furthermore, the unencapsulated devices maintain 88.6% and 91.9% of the initial PCE over 1 month in ambient air for the unmodified and Eva‐modified C‐PSCs, respectively. The study provides valuable experience for the development of highly efficient and stable C‐PSCs using common polymers for interface modification engineering.

An ionic liquid as an interface modulator for highly efficient and stable perovskite solar cells

“…The improved electron mobility and conductivity demonstrate that the charge transfer can be greatly improved with the introduction of BMIMHSO 4 , which strongly suppresses the interfacial charge accumulation; thus, achieving a high efficiency would be possible. 7,34 The optical transmission spectra for TiO 2 layer and TiO 2 -IL layer are shown in Fig. S7(a).…”

“…35 Later, the corresponding TRPL spectra are displayed in Fig. 6b and tted with the bi-exponential decay function (7).…”

“…5,6 However, it is still below the ideal (31.64%) Shockly-Queisser limit efficiency. 7 In addition, its stability is far from the commercial standard in environments with complicated heat and humidity surroundings. Hence, an improvement in the PCE and stability are essential to achieve commercialization of the device, particularly when it is manufactured in an atmosphere without a glovebox.…”

Enhanced Perovskite Photovoltaics with Non-conjugated Polymers: Recent Developments and Future Prospects

“…(f) Action mechanism of the Eva spacer layer in carbon-based PSCs. Reproduced with permission from ref . Copyright 2022 Wiley-VCH.…”

Robust electron transport layers of SnO2 for efficient perovskite solar cells: recent advances and perspectives

“…They introduced a polymer molecule poly(ethylene- co -vinyl acetate) (Eva) as an interfacial modifier at the SnO 2 /perovskite interface to reduce interfacial defects and non-radiative recombination losses between the interfaces. 139 The Fourier transform infrared (FTIR) spectra show that the main physical interaction between Eva and SnO 2 is adhesion, forming a dense SnO 2 /Eva adhesion structure, which seals the pores on the surface of the SnO 2 ETL and forms a barrier to prevent the carbon electrode from coming in contact with the SnO 2 ETL to avoid current leakage, thereby improving conductivity. The champion PCE of C-PCE with the FTO/SnO 2 /Eva/MAPbI 3 /carbon structure prepared in the air reached 12.29%.…”