Production of flexible zinc oxide-perovskite based photodetector and analysis of their characteristic properties

Within the scope of this thesis, solid-state MSM photodetector and quasi-solid-state self-powered photodetector (PD) devices were produced on flexible substrates by depositing Mn-doped and pristine ZnO nanorods (ZnO-NR) and lead-based and lead-free all-inorganic halide perovskites. Flexible thin films were synthesized by doping 5% and 9% molar percent Mn into 16.5 mM and 3.5 mM ZnO on polyimide (PI) substrates, followed by depositing interdigital Pt contact designed as a metal contact. The synthesized flexible thin films based on Mn-doped and pristine ZnO-NR were characterized via XRD, PL, SEM, and UV-vis measurements to delve into the material properties. These structural characterizations indicated that Mn atoms were successfully inserted into the ZnO crystal lattice structure which resulted in enhancement in light absorption properties and the PD performance. The key parameters of the PD devices including D*, R, S%, and EQE(%) were evaluated after conducting electrical measurements. 5%Mn:ZnO- Upon 15 V of applied potential with 367 nm wavelength of light, NR3.5-based PD device D* has D*, R, S% and EQE(%) values as 6.38x1012, 10.768 A/W, S% 3x104 and 3,645, respectively. The rise time (τr) and fall time (τd) values of the 5%Mn:ZnO-NR3.5-based PD under UV (367 nm:2.42 mW/cm2) light were evaluated as 32.2 s and 41.9 s, respectively. Under white light illumination with 840 mW/cm2 of power density, the τr and τd values were determined as 0.3 s. In addition to this significant performance, the PD device exhibited durability and stability upon consecutive concave and convex bending for 9,500 times. D* value of 9%Mn:ZnO-NC16.5 photodetector; 1.85x1014, R value; 159.467 A/W, S% value; 1.6x106 and EQE(%) value; It was calculated as 54. The τr and τd values of the 9%Mn:ZnO-NR16.5 -PD at UV light illumination (367 nm) were found to be 21.1 s and 57 s, respectively. Under white light (840 mW/cm2), the τr and τd values were determined as 0.91 s and 4.19 s, respectively. This sample also showed remarkable durability upon concave and convex bending 10,000 times. İTOPET substrate was used for the flexible Quasi-solid-state PEC self-powered photodetector. After the synthesis of Mn-doped ZnO-NR on ITOPET, the CsPbBr3 perovskite structure was synthesized and a photodetector device was obtained. UV-vis, SEM, and UV-vis measurement of ITOPET/5%Mn:ZnO-NR/CsPbBr3 thin film was taken for 17 weeks, and there was a small decrease of 7% at the 538 nm wavelength. A significant increase in PD efficiency was observed with the addition of CsPbBr3 onto 5%Mn:ZnO-NR. D* value of ITOPET/5%Mn:ZnO-NR/CsPbBr3 photodetector under 400 nm (2.99 mW/cm2) wavelength light with no applied bias, D*, R, S% and EQE(%) values were evaluated as 2.83x1012, 95.12 mA/W, 8.04x106 and 29.55, respectively. The rise time and fall time values of the ITOPET/5%Mn:ZnO-NC/CsPbBr3 photodetector under UV (400 nm) light were found to be 10.62 ms and 42.9 ms. This photodetector was turned on and off 125 times under AM1.5 (100 mW/cm2) light and on and off 53 times under 400 nm light, and current-time measurements were taken, and stability was demonstrated. In addition, current-time measurements were taken by turning on and off 27 times under 400 nm wavelength light at different angles (35o, 45o, and 60o). Under AM1.5 light, the rise time was 13.33 ms and the fall time was 50.91 ms. In addition, it was observed that this detector still exhibited photodetector properties in the current-time measurement made at the end of 12 weeks. The quasi-solid-state flexible and self-powered PD device was produced using a double-layer perovskite (Cs2AgBiBr6). SEM analysis of ZnO-NR3K and ZnO-NR3K Cs2AgBiBr6 thin films and XRD measurement of Cs2AgBiBr6 crystal were taken. The rise time of the ITOPET/ZnO-NR/Cs2AgBiBr6 photodetector under 0 V voltage and 382 nm wavelength light was found to be 16.6 ms and the fall time was 8.76 ms. In addition, current-time measurements were taken by turning the light on and off 50 times under 382 nm wavelength light at different angles (35o, 45o and 60o). Key Words: Photodetector, Flexible, Polyimide, ITOPET, ZnO, Perovskite