| 초록 |
Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted considerable attention due to their remarkable power conversion efficiency (PCE) that lately exceeds 22 %. However, stability issue remains regarding their use in real-life environments with the most urgent matter being their long-term stability under air conditions. The hybrid perovskites are inherently vulnerable to water molecules, which can induce degradation of perovskite photoactive chemicals such as MAPbI3, FAPbI3. Therefore, to realize the commercial-level long-term PSC stability, the adsorption and infiltration of water into perovskite films must be minimized. Herein, it is demonstrated that polydimethylsiloxane (PDMS) introduced simultaneously during perovskite spin-coating is highly beneficial to passivate perovskite grains and adjacent grain boundaries (GBs). It promotes the formation of lead oxide (PbO) bonding that contributes to reducing a Pb defect density related to trap-assisted recombination. Owing to the reduced trap-assisted recombination, the best PDMS-passivated PSC exhibits a PCE of 16.16 %, FF of 70 % and Jsc of 21.10 mA/cm2. The photovoltaic performance of the PDMS-passivated PSC is notably enhanced compared to a reference PSC. Furthermore, the PDMS with abundant methyl moieties is hydrophobic, effectively limiting water infiltration into the perovskite film and PbO bonding formed by PDMS passivation can prevent catalytic reaction between Pb atoms and water molecules. Thus surprisingly, more than 90 % of the initial PCE (~15 %) is sustained after laboratory storage of 5000 h under 70 % relative humidity, while only 20 % of original PCE of reference PSC is retained after 2000 h under the same conditions. These results will pave the way for developing commercial perovskite optoelectronic devices. |
