Inkjet-Printed Organohalide 2D Layered Perovskites for High-Speed Photodetectors on Flexible Polyimide Substrates

The synthesis of solution-processed two-dimensional (2D) layered organohalide (CH3(CH2)(3)NH3)(2)(CH3NH3)(n-1)PbnI3n+1(n = 2, 3, and 4) perovskites is presented, where inkjet printing was used to fabricate heterostructure flexible photodetector (PD) devices on polyimide (PI) substrates. Inks for the n = 4 formulation were developed to inkjet-print PD devices that were photoresponsive to broadband incoming radiation in the visible regime, where the peak photoresponsivity R was calculated to be similar to 0.17 A/W, which is higher compared to prior reports, while the detectivity D was measured to be similar to 3.7 x 10(12) Jones at a low light intensity F approximate to 0.6 mW/cm(2). The ON/OFF ratio was also high ( similar to 2.3 X 10(3)), while the response time tau on the rising and falling edges was measured to be tau(rise) approximate to 24 ms and tau(fall) approximate to 65 ms, respectively. Our strain-dependent measurements, conducted here for the first time for inkjet- printed perovskite PDs, revealed that the I-p decreased by only similar to 27% with bending (radius of curvature of similar to 0.262 cm(-1)). This work demonstrates the tremendous potential of the inkjet-printed, composition-tunable, organohalide 2D perovskite heterostructures for high-performance PDs, where the techniques are readily translatable toward flexible solar cell platforms as well.