Zn‐Cu‐In‐S‐Se Quinary “Green” Alloyed Quantum‐Dot‐Sensitized Solar Cells with a Certified Efficiency of 14.4 %

Abstract

The photoelectronic properties of quantum dots (QDs) have a critical impact on the performance of quantum‐dot‐sensitized solar cells (QDSCs). Currently, I‐III‐VI group QDs have become the mainstream light‐harvesting materials in high‐performance QDSCs. However, it is still a great challenge to achieve satisfactory efficiency for light‐harvesting, charge extraction, and charge collection simultaneously in QDSCs. We design and prepare Zn0.4Cu0.7In1.0SxSe2−x (ZCISSe) quinary alloyed QDs by cation/anion co‐alloying strategy. The critical photoelectronic properties of target QDs, including band gap, conduction band energy level, and density of defect trap states, can be conveniently tailored. Experimental results demonstrate that the ZCISSe quinary alloyed QDs can achieve an ideal balance among light‐harvesting, photogenerated electron extraction, and charge‐collection efficiencies in QDSCs compared to its single anion or cation quaternary alloyed QD counterparts. Consequently, the quinary alloyed QDs boost the certified efficiency of QDSCs to 14.4 %, which is a new efficiency record for liquid‐junction QD solar cells.

Studies on copper indium selenide/Zinc sulphide semiconductor quantum dots for solar cell applications

“…Hence, the bandgap of the QDs absorber ought to be greater than the difference between electrolyte redox potential and conduction level of EC [34]. Furthermore, there is a report demonstrating that 0.25 eV of energy is enough to achieve a better electron injection rate [35]. The conduction level of absorbing materials should be aligned to 0.25 eV or more than the conduction level of EC material and the valence level of excitonic absorber should be aligned to less than the electrolyte level of HC material.…”

Synthesis and structure design of I–III–VI quantum dots for white light-emitting diodes

“…Over the past decades, quantum dots (QDs) have been widely studied due to their unique optical properties such as controllable fluorescence emission and high color purity. [1][2][3] They have broad application prospects in solar cells, 4,5 bioimaging, 6,7 photocatalysis, 8,9 and light-emitting diodes (LEDs). 10,11 At present, the II-VI QDs represented by CdSe QDs are up to commercial standards.…”

Synergistic tailoring of band structure and charge carrier extraction in “green” core/shell quantum dots for highly efficient solar energy conversion

“…are regarded as favorable substitutes of Pb and Cd-based QDs due to their environmental friendliness and excellent optical properties including wide photoluminescence tunability, broadband light absorption, large Stokes shift, and high luminescence efficiency, which have been widely applied in various optoelectronic devices including light-emitting diodes (LEDs), solar cells, luminescent solar concentrators (LSCs) and PEC cells. [24][25][26][27][28][29][30][31][32][33][34][35][36][37].…”