Studying the aging effects in Hetero-structured Nb:TiO2/TiO2 based all-inorganic Perovskite solar cells
Recent promising results and the prospect for obtaining temperature-stable devices by removing organic cations are generating high expectations in CsPbI3-based perovskite solar cells (PSCs). However, the JV hysteresis is large and the power conversion efficiencies (PCEs) are still lower compared to devices based on hybrid organic-inorganic perovskites. Various improvements have been achieved in PSCs by incorporating interlayers between the perovskite and the ETL. Herein, we propose a new approach consisting of the introduction of a thin (1-2 nm) 0.5% Nb:TiO2 film between the CsPbI3 perovskite and the pristine TiO2 (hetero-ETM). This approach integrates both the passivation effect observed in our previous study and an interfacial dipole between ETL/perovskite, increasing the driving force for the extraction of electrons. The aim of this study is to compare the device stability of hetero-ETM based all inorganic PSCs respect to bulk 0.5%Nb doped TiO2 based PSCs.
Status: Ongoing
Date of proposal: 30/11/2022
Start date: 03/01/2023
End Date: 17/01/2023
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Used Instruments: HZB_MPP-Ageing infrastructure.
Experimental Technique: Studying the aging effects in hetero-structured Nb:TiO2/TiO2 based all-inorganic perovskite solar cells. Utilizing an UV filter in the MPP-ageing experiment to avoid photocatalytic degradation processes induced by TiO2.
Experiment Description: The project focused on testing the stability effects generated by the insertion of a thin interlayer of Nb:TiO2 with respect to the bulk doped Nb TiO2. The experiment included testing samples with a 0.5% Nb-doped TiO2 layer and comparing them with reference samples and those with different thicknesses of Nb-doped TiO2 layers.
Type Samples: All-inorganic perovskite solar cells with Nb:TiO2/TiO2 hetero-structures.
Sample Description: Samples containing 0.5% Nb-doped TiO2 as a reference and others with a thin (1 and 2 nm) 0.5% Nb-doped TiO2 layer deposited on top of pristine TiO2.
Experiment Data Type: Maximum Power Point Tracking (MPPT) results. Comparison of performance and stability between different samples.
Characterization Technics: MPP-ageing experiment with UV filter. Analysis of MPPT results and degradation processes.
Characterization Data Type: Photovoltaic efficiency data at different time intervals. Analysis of degradation patterns in the devices.
Analyzed Data: Comparative analysis of the impact of Nb-doped TiO2 layer thickness on device stability. Insights on the stability and aging effects in perovskite solar cells.
Main Targets Project: Investigating the stability effects of Nb:TiO2 interlayer in perovskite solar cells. Understanding the design of stable interfaces in perovskite solar cells (PSCs).
Main Achievements Findings: Observed very low efficiency and stability in devices from the start, likely due to manufacturing problems. Identified the need for pre-experiments like short-term MPP-tracking before long-term experiments. Found that the efficiency extracted at 0 hours was well below the half of the PCE extracted in fresh devices. Concluded that results might be misleading due to potential issues during manufacturing, impacting the study of the thin Nb-doped TiO2 layer's impact on solar cell stability.