Cosensitized Quantum Dot Solar Cells with Conversion Efficiency over 12%

Abstract

The improvement of sunlight utilization is a fundamental approach for the construction of high-efficiency quantum-dot-based solar cells (QDSCs). To boost light harvesting, cosensitized photoanodes are fabricated in this work by a sequential deposition of presynthesized Zn-Cu-In-Se (ZCISe) and CdSe quantum dots (QDs) on mesoporous TiO films via the control of the interactions between QDs and TiO films using 3-mercaptopropionic acid bifunctional linkers. By the synergistic effect of ZCISe-alloyed QDs with a wide light absorption range and CdSe QDs with a high extinction coefficient, the incident photon-to-electron conversion efficiency is significantly improved over single QD-based QDSCs. It is found that the performance of cosensitized photoanodes can be optimized by adjusting the size of CdSe QDs introduced. In combination with titanium mesh supported mesoporous carbon as a counterelectrode and a modified polysulfide solution as an electrolyte, a champion power conversion efficiency up to 12.75% (V = 0.752 V, J = 27.39 mA cm , FF = 0.619) is achieved, which is, as far as it is known, the highest efficiency for liquid-junction QD-based solar cells reported.

Improved Processability and Efficiency of Colloidal Quantum Dot Solar Cells Based on Organic Hole Transport Layers

“…[3][4][5][6][7][8][9][10][11][12] In the research on CQD surface engineering, effective halide-passivation successfully reduced the trap state density of CQDs, achieving increased charge drift and charge diffusion. [3][4][5][6][7][8][9][10][11][12] In the research on CQD surface engineering, effective halide-passivation successfully reduced the trap state density of CQDs, achieving increased charge drift and charge diffusion.…”

Boosting the Performance of Environmentally Friendly Quantum Dot‐Sensitized Solar Cells over 13% Efficiency by Dual Sensitizers with Cascade Energy Structure

“…[6,[13][14][15][16] The PCEs of CIS and CISe-based QDSCs have been improved steadily from less than 1% to over 8%. [5] The obtained high PCE is ascribed to the synergistic advantages of the co-sensitizers, that is, wide light absorption range from ZCISe QDs, and high extinction coefficient from CdSe. [6] More recently, an average PCE of 12.65% (without a third-party certified value) was obtained by a cosensitization approach with use of ZCISe and CdSe QDs as cosensitizers.…”

“…This demonstrates undoubtedly the improved QD loading amount, indicating that the cosensitization approach can favor the improvement of the total QD loading amount on TiO 2 . [5] This will be further discussed in the following section. [5] In QDSCs, there is a large portion (≈65%) of the TiO 2 substrate exposed to the electrolyte directly (not covered by QDs), increasing the probability of charge recombination at TiO 2 /electrolyte interface.…”

“…[1][2][3][4] In the past few years, the power conversion efficiency (PCE) of liquid-junction QDSCs has been improved from less than 5% to over 12%, [5][6][7][8] which is still below with those of the emerging inorganic photovoltaic technologies such as perovskite CsPbI 3 QD-based solar cells. [1][2][3][4] In the past few years, the power conversion efficiency (PCE) of liquid-junction QDSCs has been improved from less than 5% to over 12%, [5][6][7][8] which is still below with those of the emerging inorganic photovoltaic technologies such as perovskite CsPbI 3 QD-based solar cells.…”

“…To evaluate the effect of cosensitization on the total QD loading amount, the inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis was performed for ZCISe, ZCIS, and ZCISe/ZCIS-sensitized TiO 2 films and the detailed results are listed in Table S3 (Supporting Information). [5] In QDSCs, there is a large portion (≈65%) of the TiO 2 substrate exposed to the electrolyte directly (not covered by QDs), increasing the probability of charge recombination at TiO 2 /electrolyte interface. This demonstrates undoubtedly the improved QD loading amount, indicating that the cosensitization approach can favor the improvement of the total QD loading amount on TiO 2 .…”