Efficient and Stable Carbon-Based Perovskite Solar Cells Enabled by Mixed CuPc:CuSCN Hole Transporting Layer for Indoor Applications

Perovskite solar cells (PSCs) are an innovative technology with great potential to offer cost-effective and high-performance devices for converting light into electricity that can be used for both outdoor and indoor applications. In this study, a novel hole-transporting layer (HTL) was created by mixing copper phthalocyanine (CuPc) molecules into a copper(I) thiocyanate (CuSCN) film and was applied to carbon-based PSCs with cesium/formamidinium (Cs0.17FA0.83Pb(I0.83Br0.17)3) as a photoabsorber. At the optimum concentration, a high power conversion efficiency (PCE) of 15.01% was achieved under AM1.5G test conditions, and 32.1% PCE was acquired under low-light 1000 lux conditions. It was discovered that the mixed CuPc:CuSCN HTL helps reduce trap density and improve the perovskite/HTL interface as well as the HTL/carbon interface. Moreover, the PSCs based on the mixed CuPc:CuSCN HTL provided better stability over 1 year due to the hydrophobicity of CuPc material. In addition, thermal stability was tested at 85 °C and the devices achieved an average efficiency drop of approximately 50% of the initial PCE value after 1000 h. UV light stability was also examined, and the results revealed that the average efficiency drop of 40% of the initial value for 70 min of exposure was observed. The work presented here represents an important step toward the practical implementation of the PSC as it paves the way for the development of cost-effective, stable, yet high-performance PSCs for both outdoor and indoor applications

An Investigation into the Hydrogen Storage Characteristics of Ca(BH₄)₂/LiNH₂ and Ca(BH₄)₂/NaNH₂: Evidence of Intramolecular Destabilization

We report a study of the hydrogen storage properties of materials that result from ball milling Ca­(BH₄)₂ and MNH₂ (M = Li or Na) in a 1:1 molar ratio. The reaction products were examined experimentally by powder X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry (TGA/DSC), simultaneous thermogravimetric modulated beam mass spectrometry (STMBMS), and temperature-programmed desorption (TPD). The Ca­(BH₄)/LiNH₂ system produces a single crystalline compound assigned to LiCa­(BH₄)₂(NH₂). In contrast, ball milling of the Ca­(BH₄)/NaNH₂ system leads to a mixture of NaBH₄ and Ca­(NH₂)₂ produced by a metathesis reaction and another phase we assign to NaCa­(BH₄)₂(NH₂). Hydrogen desorption from the LiCa­(BH₄)₂(NH₂) compound starts around 150 °C, which is more than 160 °C lower than that from pure Ca­(BH₄)₂. Hydrogen is the major gaseous species released from these materials; however various amounts of ammonia form as well. A comparison of the TGA/DSC, STMBMS, and TPD data suggests that the amount of NH₃ released is lower when the desorption reaction is performed in a closed vessel. There is no evidence for diborane (B₂H₆) release from LiCa­(BH₄)₂(NH₂), but traces of other volatile boron–nitrogen species (B₂N₂H₄ and BN₃H₃) are observed at 0.3 mol % of hydrogen released. Theoretical investigations of the possible crystal structures and detailed phase diagrams of the Li–Ca–B–N–H system were conducted using the prototype electrostatic ground state (PEGS) method and multiple gas canonical linear programming (MGCLP) approaches. The theory is in qualitative agreement with the experiments and explains how ammonia desorption in a closed volume can be suppressed. The reduced hydrogen desorption temperature of LiCa­(BH₄)₂(NH₂) relative to Ca­(BH₄)₂ is believed to originate from intramolecular destabilization