A high performance organic integrated device (OID) has been realized with a thermally activated delayed fluorescence (TADF) material namely, 4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN) and another transport material named 4,7-diphenyl-1, 10-Phenanthroline (Bphen) with an interbedded architecture as the active layer. The OID had a high detectivity of 0.8×1012 Jones at -1 V under the UV-365 nm illumination with an intensity of 0.2 mW/cm2, and yielded an exciplex EL light emission with a maximum luminance of ~12000 cd/m2. While the non-intebedded device has a detectivity of 4.1×1010 Jones and a maximum luminance of 8300 cd/m2.
We demonstrated ultraviolet organic photodetectors based on poly(N-vinylcarbazole) polymeric matrix (PVK) and phosphorescent material of bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2'] iridium(acetylacetonate) [(t-bt)2Ir(acac)] blend film. The structures are the indium-tin oxide (ITO)/PEDOT : PSS/PVK/Bphen/Ag and ITO/PEDOT : PSS/PVK : (t-bt)2Ir(acac) (1 : 10 %wt)/Bphen/Ag. Under UV light illumination, a high photocurrent density of 3.44 mA/cm2 at -4 V was obtained, which is 6.6 times higher than that of without (t-bt)2Ir(acac) material. The superior performances of the device doped with (t-bt)2Ir(acac) material resulted from the UV light absorption efficiency and triplet nature of the phosphorescent complex.
Charge carrier losses of organic solar cells (OSCs) based on Subphthalocyanine (SubPc)/C60 heterojunction have been
studied through the measurements of incident light intensity dependent response of the device. The light intensity was
varied between 0.03 and 100 mW/cm2. The results showed that short circuit current density follows a linear dependence
on light intensity (Pin), while open circuit voltage logarithmically increase with Pin with a slop of 120 mV/decade,
indicating that the charge carrier losses are governed by trap-assisted recombination through interface states between
donor and acceptor, with an estimated trap density of order 1024 m-3. Moreover, the inverse dependence of shunt
resistance (RPA) on light intensity reveals that charge carriers are trapped in the bulk of active layer as well as at the
organic/electrode interface, resulting in the decrease of fill factor (FF) with Pin.
Proc. SPIE. 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
Efficient organic photovoltaic cells based on a phosphor of (t-bt)2Ir(acac) were demonstrated. Also, the photovoltaic
performances of organic solar cells with a device structure of ITO/(t-bt)2Ir(acac):CuPc (doping rate R=0 and
0.25)/C60/BCP/Ag were determined based on the current density (J)-voltage (V) curves of a series of devices. The
absorption spectra of doping layer (t-bt)2Ir(acac):CuPc and C60 films on quart substrates were measured to gain a direct
insight of absorption ability of dopant (t-bt)2Ir(acac). Then, revised optical transfer matrix theory was adopted to study
inner effect of dopant (t-bt)2Ir(acac) on the enhanced device performance, which shows that (t-bt)2Ir(acac) dopant
increases the light density of doping layer by reorganizing the light distribution inside organic films. However, the light
absorption efficiency ηA of device with R=0.25 does not improve. According to the unchanging value of open circuit
voltage VOC and similar fill factor FF, the assumption that two devices with R=0 and 0.25 possess similar charge carrier
collection efficiency ηCTηCC can be made. Thus, the inner enhancement of exciton diffusion efficiency ηED is discovered
with the assistance of longer triplet exciton diffusion length of (t-bt)2Ir(acac).