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Large area metal halide perovskite LEDs were fabricated by inkjet printing. Homogeneous drying and crystallization was facilitated by a guided and optimized gas flow.

Both nanosecond pulses and picosecond laser pulses are used for P2 patterning of chalcopyrite (Cu(In,Ga)Se2, CIGSe) and metal halide perovskite solar cell absorber layers. For CIGSe, the range of the modified material visualized by photoluminescence imaging is significantly wider than the actual physical linewidth, since energy input by the laser pulses leads to material modification in the vicinity of the scribed lines. This effect does not occur with the perovskite absorber layers, where there is no apparent influence on the edge regions. From numerical calculations of the temperature depth-profiles and the surface temperature distributions it is concluded that this effect is due to the significantly lower perovskite absorber layer thickness compared to CIGSe and the nevertheless significantly higher laser fluence required for perovskite ablation. The unaffected edge regions around the P2 line in the perovskite enabled a reduction of the dead area width in the fabrication of 3-segmented mini-modules, which could be significantly reduced from 430 to 230 µm, while increasing the aperture area power conversion efficiency and also the geometric fill factor, which could be increased up to 94.6%.

Metal halide perovskites have received great attention in recent years, predominantly due to the high performance of perovskite solar cells. The versatility of the material, which allows the tunability of the bandgap, has led to its use in light emitting diodes, photo, and X ray detectors, among other optoelectronic device applications. Specifically in photodetectors, the tunability of the bandgap allows fabrication of spectrally selective devices. Utilizing a combinatorial inkjet printing approach, multiple perovskite compositions absorbing at specific wavelengths in a single printing step are fabricated. The drop on demand capabilities of inkjet printing enable the deposition of inks in a precise ratio to produce specific perovskite compositions in the printed thin film. By controlling the halide ratio in the compositions, a mixed halide gradient ranging from pure MAPbI3 via MAPbBr3 to MAPbCl3 is produced. The tunability in the absorption onset from 410 to 790 amp; 8201;nm is demonstrated, covering the whole visible spectrum, with a precision of 8 amp; 8201;nm steps for MAPb BrxCl1 amp; 8722;x 3 compositions. From this range of mixed halide perovskites, photodetectors which show spectral selectivity corresponding to the measured absorption onset are demonstrated, paving the way for use in a printed visible light spectrometer without the need for a dispersion element