Surface passivation of perovskite layers using heterocyclic halides: Improved photovoltaic properties and intrinsic stability

Interface Engineering by Thiazolium Iodide Passivation Towards Reduced Thermal Diffusion and Performance Improvement in Perovskite Solar Cells

“…The integrated current density from the external quantum efficiency (EQE) was 21.5 mA cm −2 (Figure 5b), which is in agreement with data obtained from the measurement of J–V curves reported. As previously reported,10 even in this case the optical bandgap remain unchanged after deposition of the passivation layer, and it can be stated that the low‐dimensional perovskite formed atop of the 3D perovskite does not affect the optical properties of the material. Furthermore, EQE decreases to half the peak value and the differential of the EQE (Figure S7a, Supporting Information) suggests that the absorption threshold is 1.61 eV.…”

“…Arguably, the use of a passivation layer at the perovskite/HTM interface improves the charge extraction from the perovskite and prolong the lifetime of the devices 10,16. In the past,10,17 an improvement in the V OC and the fill factor (FF) of perovskite‐based devices was reported, due to fine energy level alignment between layers that improves the charge extraction.…”

“…Arguably, the use of a passivation layer at the perovskite/HTM interface improves the charge extraction from the perovskite and prolong the lifetime of the devices 10,16. In the past,10,17 an improvement in the V OC and the fill factor (FF) of perovskite‐based devices was reported, due to fine energy level alignment between layers that improves the charge extraction. Remarkably the stability was also improved with the utilization of fluorinated‐based compounds which improves the hydrophobicity of the perovskite surface, repelling moisture, and increasing its environmental tolerance 18,19.…”

“…Due to the weak structure of perovskites, iodide anions are prone to volatility, while its diffusion induces irreversible degradation and destabilize the crystal structure. The inclusion of imidazolium iodide between perovskite and the hole selective contact to passivate the iodide vacancies in the crystal lattice was found to be an effective strategy to improve charge transport properties,10 and consequently, PV performance and durability was significantly improved. With an aim to develop new efficient passivating molecules to passivate the defect on the surface and interface between the perovskite/HTM as well as hole extraction enhancement in PSCs, we rationally design three different substituted thiazolium iodide (TMI) salts, where the presence of sulfur atom is supposed to play a pivotal role in interaction with perovskite's iodine atoms to enhance the perovskite–HTM interfacial contact and thus improves hole extraction 11.…”

Novel Surface Passivation for Stable FA0.85MA0.15PbI3 Perovskite Solar Cells with 21.6% Efficiency

“…The PL intensity of the perovskite film w TPFPB passivation exhibits a stronger band emission at 804 nm relative to the control film at the same excitation, indicating lower nonradiative recombination loss compared with the control sample . The most probable reason is that fluorine ions in the TPFPB can introduce excess halides onto the perovskite surface to compensate/fill any iodide vacancies, thereby passivating the nonradiative recombination pathways and leading to high luminescence efficiencies . Figure d shows the TRPL spectra of the perovskite film wo/w TPFPB passivation.…”