Professor Tae Geun Kim from the School of Electrical Engineering, the College of Engineering, Korea University. Photo: Korea University.

Professor Tae Geun Kim's research team from the School of Electrical Engineering at Korea University has successfully developed an organic solar cell (MemOSC) with memory and learning functions integrated on a single chip. This was achieved using a flexible transparent electrode with a multilayer structure of two-dimensional titanium carbide (Ti3C2Tx) MXene/Ag/Ti3C2Tx MXene.

Organic solar cells (OSCs) have gained attention due to their high power conversion efficiency, low cost, ultra-lightweight, mechanical flexibility, and large-area scalability. Research is ongoing to equip these devices with learning capabilities..

Developing electrodes with low sheet resistance, high transparency, and superior mechanical stability is crucial for determining the performance of all optoelectronic devices, including solar cells.

Indium tin oxide (ITO)-based electrodes are commercially used due to their high transparency and conductivity. However, they have limitations, such as low mechanical flexibility and the high cost of indium.

The research team successfully developed a flexible transparent electrode with a low sheet resistance of 9.7 Ω sq-1, high transmittance of 84%, and stable characteristics even after 2,000 bending tests by doping Zn nanoparticles on the surface of the Ti3C2Tx MXene/Ag/Ti3C2Tx MXene multilayer structure electrodes fabricated by spin-coating and sputtering, which allowed for easy control of the electrode's work function.

The memory-learning organic solar cell (MemOSC) equipped with this developed electrode demonstrated a power conversion efficiency of 13.86% and maintained stable solar performance even after hundreds of switching cycles. It also showcased excellent memory performance, including low operating voltages of 0.60 and −0.33 V, a high on/off ratio (10^3), stable durability (4 x 10^3), and excellent data retention (>10^4 seconds).

This research demonstrates that a multilayer electrode structure based on two-dimensional MXene can function well as a flexible transparent electrode for organic solar cells while simultaneously performing non-volatile memory functions with electrical readout.

Additionally, integrating energy harvesting and artificial synapse (memory, learning) functions is expected to be utilized in future energy-integrated devices and system implementations.

This research was supported by the Leader (Creative) Research Program of the Ministry of Science and ICT and the National Research Foundation of Korea (NRF). The paper was published on May 3 in the prestigious academic journal "Advanced Science" [IF: 17.521, Journal Citation Reports (JCR) ranking: top 5.94%].

Reporter: Bok Hyun-Myung (hmbok@dailysmart.co.kr)
Source: Smart Economy (https://www.dailysmart.co.kr)