Our research aims towards an economical low-carbon future. We investigate the use of nanoscale materials in next-generation photovoltaic technologies. We use multidisciplinary knowledge from physics, chemistry and materials science to engineer high performance multi-layered thin film solar cells with nanoscale materials and characterize their performance. In particular, we fabricate and characterize solution-processed organic and perovskite solar cells, both of the devices have shown great potential for commercial application.
In UNSW we have already developed low temperature processed efficient organic (12.5%) and perovskite (19%) solar cells for the roll-to-roll manufacturing on flexible substrates. We have also develop semi-transparent efficient organic (7.3%) and perovskite (11.5%) solar cells with 25% average visible transmission (AVT). We are also working on organic/perovskite tandem solar cells.
OPV research team: From left – back row: Pengdong Jian, Eric Tong, Hao Lian, Wenyan Tao, Cheng Xu; middle row – Tat Ming Cheng, Faiazul Haque, Anbang Wang, Leiping Duan, Haimang Yi; front row – Qingge Feng, Mushfika Baishakhi Upama, Ashraf Uddin, Dian Wang and Arafat Mahmud.
OPV group meeting: From left: Kah Chan, Ashraf Uddin, Gavin Conibeer, Christoph Brabec, Naveen Kumar Elumalai, Arafat Mahmud, Mushfika Baishakhi Upama and Matthew Wright
Key research areas
Our research strengths are in the areas of development of process technology for the fabrication of high efficiency devices, electrical and optical characterisations of materials and devices, mathematical modelling and design of new OPV devices for commercial applications. For more details please discuss with the principal investigator- A/Prof. Ashraf Uddin.
Semitransparent organic solar cell
[REF: M.B. Upama et al. (2017) ACS Photonics 4 (9), 2327-2334]
Aim: Develop high efficiency bulk hetero-junction OPV cells by blending donor and acceptor materials together on indium tin oxide (ITO) coated glass substrate. We are trying to optimize the donor-acceptor morphology. If the morphology could be controlled on a molecular scale the efficiency of charge separation and transport could be expected to be substantially higher.
Outcomes: At present two PhD students are working in this project. Three PhD students are already graduated from this project. 15 journal papers and seven international conference proceeding papers are already published and four journal papers are under review for publication.
(ii) Ternary blend organic solar cell
Aim: The concept of ternary blend solar cell is the two electron donor materials or two acceptor materials with complementary properties are mixed with an electron acceptor or electron donor, respectively to overcome some of the limitations of binary blend OPV devices. This approach leads to a concurrent optimisation of short circuit current density and open circuit voltage, through careful choice of the complementary materials. An elegant strategy of designing a ternary solar cell is to extend the photocurrent generation into the near infra-red region by incorporating a low band gap polymer or dye into a large band gap polymer host system.
Outcomes: Seven journal papers are already published and two journal papers are under preparation for publication. One PhD student is graduated from this project and two PhD students are working for the completion of degree.
Aim: High efficiency semitransparent organic solar cells are a promising approach to smart window applications and building integration with average visible transmittance (AVT) of 25%. To achieve semi-transparency, multilayered structures, especially, dielectric/metal/dielectric (D/M/D) have shown promise as transparent electrodes. There is a trade-off between photovoltaic performance and visible transparency of the device. It is also important to gain a high color rendering index (CRI) to ensure that the original color of an object is perceived by human eye.
Outcomes: We have already developed high-efficiency (7.3%) semitransparent organic solar cells based on a novel fullerene-free material system with 25% AVT for the first time. Three journal papers are published and one manuscript is under review for journal publication. At present one PhD student is working in this project.
Optical modelling of thin film solar cell
Spatial distribution of the normalized electric field intensity for incident light
[REF: M.B. Upama et al. (2017) Optical and Quantum Electronics 49 (1), 28]
Low-temperature processed ZnO electron transport layer for perovskite solar cell
[REF: M.A. Mahmud et al. (2017) Solar Energy Materials and Solar Cells 159, 251-264]
Photographs of a flower with and w/o semitransparent solar cells
[REF: M.B. Upama et al. (2017) Current Applied Physics 17 (2), 298-305]
Hole transport layer modification for perovskite solar cells
Effect of HTL modification in perovskite solar cell stability
[REF: M.A. Mahmud et al. (2017) PCCP 19 (31), 21033-21045]
Thin-film tandem solar cells
Details coming soon!
(iv) Encapsulation of OPV devices
Aim: The overall stability of organic and perovskite solar cells is dependent on the stability of the actual photoactive component, the barrier and substrate layers and the interfacial stability. Suitably transparent and high barrier encapsulation materials and structures can further extend device stability and life expectancy providing sufficient durability for commercial application. Encapsulation materials have to meet the requirements of good process ability, high optical transmission, high dielectric constant, low water absorptivity and permeability, high resistance to ultra-violet (UV) degradation and thermal oxidation, good adhesion, mechanical strength, and chemical inertness.
Outcomes: One PhD student is graduated in this project. We have already produced some valuable data. In future one/two more PhD students will work in this area.
Aim: We are working on the low temperature processed perovskite solar cells for the roll-to-roll fabrication. In UNSW we have already developed low temperature processed perovskite solar cells with efficiency around 19%, within 4% of the current world record. These solar cells exhibit high power conversion efficiencies of great potential in real applications.
Outcomes: Twelve journal papers are published and another three manuscripts are under review for publications. Two PhD students are already graduated from this project. At present two PhD students are working in this project.
Aim: The aim of this project is to develop high efficiency tandem solar cells on the basis of the applicants’ extensive experience and establish tandem cells processing capability in UNSW. The goal is to use our capability to develop and fabricate high efficiency tandem solar cells.
Outcomes: Two patents are developed for commercial applications. Future Solar Technology Pty Ltd has invested around $1.5 million to develop this technology in UNSW. At present two PhD students are working in this project. One/two more PhD students will be hired to work in this project in near future.