Triamine‐Based Aromatic Cation as a Novel Stabilizer for Efficient Perovskite Solar Cells

Abstract

Operational stability of perovskite solar cells has been a challenge from the beginning of perovskite research. In general, humidity and heat are the most well‐known degradation sources for perovskites, requiring ideal design of perovskite chemistry to withstand them. Although triple‐cation perovskite (Cs0.05(FA0.85MA0.15)0.95Pb(I0.85Br0.15)3) has been already introduced as the stable perovskite material, the high reactivity of methylammonium and formamidinium in the cation sites demands further modification. Herein, 1,2,4‐triazole is suggested as an effective cation solute to improve the performance and stability of perovskite solar cells. 1,2,4‐Triazole is an aromatic cation with low dipole moment that is stable under humidity and heat. It also possesses three nitrogen atoms, forming additional hydrogen bonds in the lattice, stabilizing the material. In this study, the solar cell utilizing 1,2,4‐triazole alloying achieves a power conversion efficiency of 20.9% with superior stability under extreme condition (85 °C/85% of relative humidity (RH), encapsulated) for 700 h. The 1,2,4‐triazole‐alloyed perovskite exhibits reduced trap density and film roughness and enhanced carrier lifetime with electrical conductivity, suggesting an ideal perovskite structure for efficient and stable optoelectronic applications.

CuCrO2 Nanoparticles Incorporated into PTAA as a Hole Transport Layer for 85 °C and Light Stabilities in Perovskite Solar Cells

“…High humidity was used to detect devices with damaged encapsulation which would undergo rapid moisture-induced degradation with a leak. As presented in Figure 5 , improved thermal stability was observed for the device with CuCrO 2 /PTAA HTL, where the device maintained over 90% of its initial PCE after 860 h. The degradation of organic cations in the perovskite or small organic molecules within HTL can critically damage both bulk and the interface, especially at an elevated temperature [ 9 , 10 , 20 , 81 , 82 ]. It can be inferred that the presence of more heat-resistant CuCrO 2 nanoparticles in the vicinity of perovskite and HTL creates a more heat-resistant interface with reduced interfacial reactions to maintain excellent thermal stability.…”

“…In the field of next-generation photovoltaics, organic-inorganic hybrid halide perovskite solar cells have gathered tremendous attention since their emergence due to their rapidly growing power conversion efficiency (PCE), micrometer-scale carrier diffusion length, high absorption coefficient over solar spectrum regions, small exciton binding energy, etc. [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. However, its relatively poor stability is still a main bottleneck toward commercialization, which becomes more serious at elevated temperatures or under constant illumination due to the rapid degradation of materials along with the accelerated formation and migration of defects [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

Extraction technique of trap states based on transient photo-voltage measurement

“…According to the literatures in recent years [19][20][21][22][23] , current density-voltage (J-V) hysteresis is caused by the ion migration and trap assisted carrier recombination. The DOS T distribution affects the carrier recombination [24][25][26][27] , influences the open circuit voltage [28][29][30] , and hinders the enhancement of power conversion efficiency (PCE) [31][32][33][34] . The DOS T distribution cannot be obtained by experimental measurement directly.…”

Inorganic Materials by Atomic Layer Deposition for Perovskite Solar Cells

“…Although PSCs have shown promising results in terms of theirs rapid progress in power conversion efficiency, already at 25.5% for unit cells [ 1 ], they are different from other PV technologies as they display other challenges especially towards long-term stability of the working devices from both external and internal factors. Device deterioration from internal factors include ion migration from the perovskite layer and from dopants of hole transport layers diffusing out into the perovskite, whereas external factors include deterioration from exposure to light, elevated temperatures, and air (moisture and oxygen) [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 ]. In order for the actual commercialization of PSCs to occur, optimization of the following aspects will be required: high efficiency, long-term stability, possible large-area coating techniques, consideration of semitransparent and tandem applications, and nontoxicity and low-cost of the materials and fabrication processes.…”