Version 2 2024-02-06, 14:34Version 2 2024-02-06, 14:34
Version 1 2023-11-20, 17:01Version 1 2023-11-20, 17:01
journal contribution
posted on 2024-02-06, 14:34authored byJong Hyun Park, Young Wook Noh, Jung Min Ha, Amit Kumar Harit, Ayushi Tripathi, Jeongjae Lee, Bo Ram Lee, Myoung Hoon Song, Han Young Woo
Perovskite defects are a major hurdle in the efficiency
and stability
of perovskite solar cells (PSCs). While various defect passivation
materials have been explored, most are insulators that hinder charge
transport. This study investigates the potential of two different
π-conjugated polyelectrolytes (CPEs), MPS2-TEA and PCPDTBT2-TMA,
as semiconducting additives in PSCs. The CPEs differ in electrical
conductivity, offering a unique approach to bridge defect mitigation
and charge carrier transport. Unlike previous uses of CPEs mainly
as interlayers or charge transport layers, we explore their direct
effect on defect passivation within a perovskite layer. Secondary
ion microscopy reveals the even distribution of CPEs within the perovskite
layer and their efficient defect passivation potential is studied
through various spectroscopic analyses. Comparing MPS2-TEA and PCPDTBT2-TMA,
we find MPS2-TEA to be superior in defect passivation. The highly
conductive nature of PCPDTBT2-TMA due to self-doping diminishes its
defect passivation ability. The negative sulfonate groups in the side
chains of PCPDTBT2-TMA stabilize polarons, reducing defect passivation
capability. Finally, the PSCs with MPS2-TEA achieve remarkable power
conversion efficiencies (PCEs) of 22.7% for 0.135 cm2 and
20.0% for large-area (1 cm2) cells. Furthermore, the device
with MPS2-TEA maintained over 87.3% of initial PCE after 960 h at
continuous 1-sun illumination and 89% of PCE after 850 h at 85 °C
in a nitrogen glovebox without encapsulation. This highlights CPEs
as promising defect passivation additives, unlocking potential for
improved efficiency and stability not only in PSCs but also in wider
applications.