Tunable multicolor luminescence in vanadates from yttrium to indium with enhanced luminous efficiency and stability for its application in WLEDs and indoor photovoltaics

The preparation of high-efficiency phosphor is the key to the construction of white light-emitting diode (WLED) devices and their application in indoor photovoltaics. Compared with YVO4, InVO4 is not suitable as the host material of lanthanide ions because of its strong self-luminescence. Here, the work focused on combining the broadband emission from InVO4 and the red luminescence from YVO4:Eu3+ to obtain enhanced and stable multicolor luminescence. The band structure, density of state, and optical properties were studied by density functional theory. The spectral configuration of YVO4:In3+/Eu3+ with (112) surface appears to be broadening and redshifts with increasing layer number. When the In3+ concentration is 3.5 mol%, the YVO4:30%Eu3+/In3+ emits the strongest light. The Judd-Ofelt parameter Ω2 of YVO4:In3+/Eu3+ increases with increaing In3+ concentration, indicating that the symmetry decreases. By adjusting In3+/Eu3+ contents, the YVO4:In3+/Eu3+ not only can emit white light with a color rendering index of 95, but also can be used as high-efficiency red phosphor to build WLED devices with blue emitting N/Tb codoped carbon quantum dots (CQDs-N:Tb3+) and green emitting MOF:Tb3+ (MOF = metal organic framework), for which the color rendering index can also reach 95 and the color temperature is 5549 K. The manufactured WLED devices were further used to excite the silicon solar cell and make it show good photoelectric characteristics.