Preparation of High-Efficiency (>14%) HTL-Free Carbon-Based All-Inorganic Perovskite Solar Cells by Passivation with PABr Derivatives

Abstract

Due to the advantages of low cost and good thermal stability, all-inorganic CsPbI 2 Br carbon-based perovskite solar cells (C-PSCs) without a hole transport layer have been rapidly developed in recent years. While the carbon electrode is in direct contact with the CsPbI 2 Br film, higher requirements are placed on the defects and energy level arrangement of the CsPbI 2 Br layer, which leads to the relatively low photoelectric conversion efficiency (PCE) of C-PSCs. Herein, propylamine hydrobromide (PABr) and its derivative 3-bromopropylamine hydrobromide (3Br-PABr) were used to passivate the surface defects of CsPbI 2 Br C-PSCs for the first time. The results show that passivation molecules are modulated by the substituent effect, leading to a stronger interaction between amino groups and uncoordinated Pb 2+ ions, which facilitates a better passivation effect of 3Br-PABr. In addition, 3Br-PABr promotes the gradient arrangement of energy levels while passivating surface defects, which accelerates the rapid extraction of holes. After the passivation by PABr and 3Br-PABr, the PCE of HTL-free CsPbI 2 Br C-PSCs increased from 12.15% for the control device to 13.15 and 14.04%, respectively, which are among the highest reported values of CsPbI 2 Br C-PSCs.

Acetate-Assisted Buried Interface Engineering for Highly Efficient Carbon-Based CsPbI2Br Perovskite Solar Cells

“…Surprisingly, under the optimal Zn­(Ac) 2 concentration of 0.5 mg/mL (other concentrations and corresponding device performances are shown in Table S2 and Figure S8), a significantly enhanced PCE of 14.20% ( J sc : 14.49 mA/cm 2 ; V oc : 1.226 V; FF: 79.95%) was achieved for the target CsPbI 2 Br C-PSCs, mainly due to its dramatically increased V oc and FF values. To our present knowledge, this PCE is among the highest efficiencies of the reported CsPbI 2 Br C-PSCs, further demonstrating the effective defect regulation for the Zn­(Ac) 2 -modified buried interface. ,,,, Considering the hysteresis phenomenon existing in this kind of device (Figure S9), we evaluate the steady power output (SPO) of CsPbI 2 Br C-PSCs operated at their maximum power point, as depicted in Figure b, which reveals steady PCEs of 11.41% and 13.07% for the control and target C-PSCs, respectively. The external quantum efficiency (EQE) spectra of both devices are presented in Figure c, enabling us to determine the integrated J sc values for the control and target devices as 13.95 and 14.06 mA/cm 2 , respectively.…”

“…To our present knowledge, this PCE is among the highest efficiencies of the reported CsPbI 2 Br C-PSCs, further demonstrating the effective defect regulation for the Zn(Ac) 2 -modified buried interface. 33,35,41,52,53 Considering the hysteresis phenomenon existing in this kind of device (Figure S9), we evaluate the steady power output (SPO) of CsPbI 2 Br C-PSCs operated at their maximum power point, as depicted in Figure 5b, which reveals steady PCEs of 11.41% and 13.07% for the control and target C-PSCs, respectively. The external quantum efficiency (EQE) spectra of both devices are presented in Figure 5c, enabling us to determine the integrated J sc values for the control and target devices as 13.95 and 14.06 mA/cm 2 , respectively.…”

All‐Inorganic Perovskite Solar Cells: Modification Strategies and Challenges

“…[77] Therefore, the energy level alignment among the perovskite film and CTLs, as well as the interface properties of perovskite films (such as defect density, grain size homogeneity, and film roughness) play a critical role in determining the charge transport and trap-assisted charge recombination of the device, thereby influencing the performance of AIWPSCs. [56,74,[86][87][88] Consequently, much attention has been focused on this field. Yang and coworkers found that the top deposited polythiophene film can significantly suppress carrier recombination within the all-inorganic perovskite layer by passivating the interface defect states, which can effectively extend the carrier lifetime of the perovskite film (Figure 6a).…”

Simulation and optimization of 30.17% high performance N-type TCO-free inverted perovskite solar cell using inorganic transport materials

“…One of such efforts is the significant improvement of stability in perovskite solar cells through the use of doping engineering to create a hole transport layer free of pinholes 35 . Investigations by other scientists have concentrated on creating effective PSCs employing novel kinds of hole-transport materials as replacement to Spiro-OMeTAD 36 , 37 , or PSCs without HTL that are suitable for streamlining the device’s ideal process, and further reduce manufacturing cost and as well prevents perovskite’s degradation 38 – 40 . There is no doubt that the absence of pinholes in HTM layer considerably increases the PSC’s device stability under operating environments 41 .…”