CsPbI₂Br Perovskite Solar Cells Based on Carbon Black-Containing Counter Electrodes

Abstract

CsPbI2Br perovskite solar cells (PSCs) based on carbon electrodes (CEs) are considered to be low-cost and thermally stable devices. Nevertheless, the insufficient contact and energy level mismatch between the CsPbI2Br layer and CE hinder the further enhancement of the cell efficiency. Herein, a carbon black (CB) interlayer was introduced between the perovskite layer and CE. The hole extraction was facilitated due to the larger contact area and suitable energy band alignment in the CsPbI2Br/CB interface. Further investigation indicated the diffusion of CB nanoparticles from the CE or CB layer to the CsPbI2Br film after a certain period of time. We disclosed the formation of a CB-CsPbI2Br bulk heterojunction structure due to the carbon diffusion, which resulted in an efficiency enhancement. As a result, a record efficiency of 13.13% is achieved for carbon-based inorganic PSCs. This work also reveals that the diffusion of CB nanoparticles in CB-containing PSCs is universal and inevitable, although this kind of diffusion results in the enhancement of cell efficiency.

Carbon-based electrodes for perovskite solar cells

“…4(c) and 4(d). 48 Fig. 4 52 Under the conditions of carbon film composition (the ratio of graphite to 10 carbon black was 3:1) and hot-press pressure (0.25 MPa), the interface contact between the perovskite and carbon film was optimal.…”

“…74 Carbon nanotubes are suitable to be counter electrodes because of their unique structure to promote hole extraction, 90 while carbon black can increase the pores of carbon paste, promote charge transfer and improve interface contact. 48 Therefore, it is reasonable to believe that if the carbon materials will be utilized as the basic electrode material, the PCE will be possible catch up with that of conventional M-PSCs.…”

“…We envision that this work will inspire researchers to employ the remarkable stability, low-cost and hydrophobic properties of carbon materials to highly efficient and stable C-PSCs. 48 Copyright 2020, American Chemical Society.…”

“…(d) Energy band alignment of CB interlayerbased PSC. (e) Schematic illustration of the fabrication process of C-PSCs 48. Copyright 2020, American Chemical Society.…”

Efficient and Stable All‐Inorganic Perovskite Solar Cells

“…[43] Recently, Yang and coworkers demonstrated a promising PCE as high as 13.13% based on holeconductor-free all-inorganic PSCs (Figure 1). [44] Consequently, hole-conductor-free all-inorganic PSCs exhibit great potentials in achieving a high PCE and high stability relative to all-inorganic PSCs with HTMs ( Figure 1). Regarding inverted all-inorganic PSCs, the development of effective inorganic electron transport materials (ETMs) plays a key role in realizing high efficiency and long-term stability.…”