Nanotechnology Now Home > Press > 2D materials for conducting hole currents from grain boundaries in perovskite solar cells a,b The structural schematic diagram and energy-level band diagram of a BP-modified PSC with a normal structure. c,d Current density-voltage (J-V) curves (reverse scan) and external quantum efficiency (EQE) spectra of PSCs without (control) and with BP deposition (1~3 times) on perovskite film surface. e Histogram of power conversion efficiencies (PCEs) of PSCs without (control) and with BP modification (BP coating for 2 times). The PCEs are derived from the reverse scans of the J-V curves. f The average PCE enhancement after the modification of perovskite films with different 2-D materials.