Cu₁₂Sb₄S₁₃ Quantum Dots with Ligand Exchange as Hole Transport Materials in All-Inorganic Perovskite CsPbI₃ Quantum Dot Solar Cells

Abstract

Perovskite solar cells (PSCs) have developed rapidly in the past 10 years. However, they are faced with a huge challenge for stability improvement because of the volatile organic components in the light absorption and hole transporting layer. Herein, we fabricate all-inorganic PSCs with the structure of FTO/c-TiO 2 /m-TiO 2 /CsPbI 3 quantum dots (QDs)/Cu 12 Sb 4 S 13 QDs/Au to improve device stability. To enhance the photovoltaic performance of PSCs, the surface oleylamine ligands of Cu 12 Sb 4 S 13 QDs with 3-mercaptopropionic acid are exchanged, as the enhanced electronic coupling and reduced band gap are realized after the ligands exchange. Cu 12 Sb 4 S 13 QD based PSCs exhibit a PCE of 10.02%, approaching that of the spiro-MeOTAD based PSCs (12.14%). A high shortcircuit current density of 18.28 mA cm −2 is achieved because of the enhanced light absorption and excellent hole extraction ability of Cu 12 Sb 4 S 13 QDs. Moreover, Cu 12 Sb 4 S 13 QD based PSCs exhibit the improved long-term stability and retain 94% of their initial PCE after storage in ambient air for 360 h.

All-inorganic perovskite quantum dots as light-harvesting, interfacial, and light-converting layers toward solar cells

“…11e). 133 The crystal structure of Cu 12 Sb 4 S 13 QDs is similar to that of CsPbI 3 QDs with a very small lattice mismatch, which is conducive for pore extraction. Moreover, Cu 12 Sb 4 S 13 QD aer ligand exchange show stronger light capture ability and hole extraction ability, which further improved the J sc of the device.…”

“…Relatively, the inorganic hole transport layer could also enhance the device stability. For example, Chen et al reported Cu 12 Sb 4 S 13 QDs as hole transport materials 133 to improve the device stability. They found that the photoelectric performance of spiro-MeOTAD-based AIPQDSCs declines rapidly and drops to 42% in 360 h, while Cu 12 Sb 4 S 13 QD-based AIPQDSCs exhibit superior stability, maintaining 94% of their initial PCE under the same conditions.…”

Perovskite Quantum Dots in Solar Cells

“…To avoid these drawbacks, dopant‐free poly[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl‐alt‐3‐fluoro‐2‐[(2ethylhexyl) carbonyl]thieno[3,4‐b]thiophene‐4,6‐diyl] (PTB7) was used in CsPbI 3 PQDSCs and it exhibited efficient electron blocking and hole extraction capability as well as the surface passivation effect, which may be attributed to the sulfur and carbonyl groups, [ 108 ] thus conferring devices with excellent PCE and reasonable environmental stability. [ 109 ] In addition, inorganic Cu 12 Sb 4 S 13 QDs were also employed as HTMs in CsPbI 3 PQDSCs, [ 110 ] which possess lattice match with CsPbI 3 PQDs. Not only do they have the advantages of suitable valence band energy level, high hole mobility, and nontoxicity, but also, they are beneficial for the hole extraction.…”

Colloidal quantum dots and metal halide perovskite hybridization for solar cell stability and performance enhancement

“…The surface oleylamine ligands of CAS QDs are exchanged with 3-mercaptopropionic acid, realizing enhanced electronic coupling and reduced band gap. 109 The all-inorganic PQD SCs with CAS QDs exhibit a PCE of 10.02%, achieving a high J sc of 18.28 mA cm −2 because of the improved light absorption and hole extraction ability of CAS QDs. Moreover, CAS QD based PSCs exhibit enhanced long-term stability and retain 94% of their initial PCE after storage in ambient air for 360 h. In addition to chalcogenide QDs, QDs such as carbon QDs 50,110,111 , graphene QDs (GQDs) 112,113 , black phosphorus QDs (BPQDs) 114 etc., have emerged as efficient perovskite absorbers to improve the PCE and the stability of PSC devices.…”

“…(g) Long-term stability of PQD SCs with spiro-MeOTAD and CAS QDs HTMs in ambient air. Images are reproduced from ref 109.…”