A universal solution processed interfacial bilayer enabling ohmic contact in organic and hybrid optoelectronic devices

Abstract

A bilayer of Nb-TiO2 and bathocuproine forms a highly ohmic contact between a wide variety of semiconducting materials and metal electrodes. This enables performance and stability improvements in a range of electronic devices.

A Multilayered Electron Extracting System for Efficient Perovskite Solar Cells

“…Similar to previously observed trends, [36] the presence of the additional AZO and TPPO layers, in conjunction with PC 60 BM, lead to an enhancement in solar cell operational stability. As shown in Figure S4 (Supporting Information), in the case of PC 60 BM alone, T 80 (the time for the solar cell to reach 80% of its original PCE) is reached after 300 h. In contrast, the addition of AZO raises this time to 550 h, with the device benefitting from a reduction in metal electrode migration through the ETL and into the perovskite.…”

“…Moreover, enhanced EQE response is observed at longer wavelengths (>700 nm) for PC 60 BM/ AZO and especially for PC 60 BM/AZO/TPPO cells, which suggests reduced recombination at the "rear" side of the cell, i.e., interface between perovskite and ETL. [36] The integrated photocurrent density for the PC 60 BM, PC 60 BM/AZO, and PC 60 BM/ AZO/TPPO solar cells is 19.5, 20.6, and 20.9 mA cm −2 , respectively, in good agreement with the J SC values obtained from the J-V plots in Figure 1d. Moreover, the statistical data collected from over 20 cells ( Figure S3, Supporting Information) indicate that that triple-ETL not only improves the overall device performance, but also narrows the spread of all device parameters, which highlights the effectiveness of the new multilayer ETL to improve the reproducibility of the device manufacturing.…”

“…[36] The universality of this Nb:TiO 2 /BCP bilayer ETL was demonstrated for organic photovoltaics as well as light emitting diodes and field effect transistors. [36] Herein, we report on the use of a solution-processable bilayer ETL consisting of PC 60 BM and Al-doped zinc oxide (AZO), which forms highly Ohmic contact with the metal electrode and thus significantly outperforms PC 60 BM-only ETL cell. The device performance, in particular FF, is further improved by depositing one more layer of a solution-processed, annealing free and inexpensive small organic molecule of triphenyl-phosphine oxide (TPPO; Figure 1a).…”

“…[ 35 ] Recently, we have demonstrated a universal approach to achieve an Ohmic contact between the ETL and various thermally evaporated metal electrodes (Ag, Cu, and Au) with a bilayer of Nb:TiO 2 and BCP, achieving record high fill factors (FF) of 83% for PSCs. [ 36 ] The universality of this Nb:TiO 2 /BCP bilayer ETL was demonstrated for organic photovoltaics as well as light emitting diodes and field effect transistors. [ 36 ]…”

“…[ 36 ] The universality of this Nb:TiO 2 /BCP bilayer ETL was demonstrated for organic photovoltaics as well as light emitting diodes and field effect transistors. [ 36 ]…”