Advanced Energy Materials (IF 29.698) recently published a study. Doped Spiro-OMeTAD hole transport layer (HTL) formed by lithium bis(trifluoromethane)sulfonimide salt and 4-tert-butylpyridine and phenethylammonium iodide on perovskite thin films Surface treatments have been dominating the record power conversion efficiencies (PCEs) of perovskite solar cells (pero-SCs). However, unstable HTL compositions and iodide salts can lead to severe device degradation. The surface of the HTL film will be deteriorated due to the hygroscopicity of lithium bis(trifluoromethane)sulfonimide and the volatility of 4-tert-butylpyridine; and the iodide ion salt will accelerate the I-migration, making the perovskite active Layers will degrade. These are not conducive to the commercialization of perovskite solar cells. In this study, the research team designed a HTL composition-conditioning agent (CCA), Spiro-BD-2OEG, which contains a Spiro-OMeTAD-like backbone chain, functional pyridine units and an oligo(ethylene glycol) chains. This well-designed CCA exhibits good miscibility with Spiro-OMeTAD and its dopants, and acts as a conditioning agent through weak bond interactions. As a result, the CCA- regulated HTL exhibits a pinhole-free and smooth morphology with enhanced Spiro-OMeTAD ordering and improves dopant stability. Furthermore, the gradient-distributed CCA in the HTL can narrow the energy level offset with the valence band of the perovskite.

　　Enlitech’s Solar Simulator, QE-R Quantum Efficiency Measurement system and other instruments were used in this study to assist in the measurement. The results showed that:

1.  The resultant pero-SCs exhibit an excellent PCE of 24.19% without any interface treatment and weak size dependence.
2. Even for a 1.004 cm² device, a significant PCE of 22.63% is obtained.
3. Importantly, the strategy shows good versatility and substantially contributes to the long-term stability of the pero-SCs based on the classical doped Spiro-OMeTAD.

　　In addition to the EQE (External Quantum Efficiency) spectrum analysis of solar cells, the Quantum Efficiency Measurement System of Enlitech also provides Jsc (short-circuit current density) comparison for the short-circuit current of solar cells under the solar simulator to prove the authenticity of the experiment.