Light Harvesting
The Light Harvesting Sub-group focuses on the development of low-cost devices that convert incident photons into usable forms of energy, such as electricity or fuels. By leveraging both wet and dry chemistry techniques, our team fabricates next-generation thin-film light-harvesting devices, including perovskite solar cells, perovskite photodetectors, and metal oxide photoelectrochemical cells.
Our fabrication methods include slot-die coating, spin-coating, atomic layer deposition, and multi-source thermal evaporation. For device characterisation, we employ a comprehensive suite of techniques, such as capacitance-voltage, multiplexor current–voltage measurements, impedance measurement, sensitive external quantum efficiency analysis, long-term stability testing (e.g., maximum power point tracking) and some home-built unique optoelectronic characterisation methods, including operando photoluminescence (PL) spectroscopy and hyperspectral PL microscopy for in-situ device analysis.
Device Fabrication and Characterization Facilities
Check More from here: Solar Suite, Maxwell Ambient Cluster, three more new glove boxes, one thermal evaporator and another ALD system are coming.
Multi-junction solar cells
Our work on tandem solar cells centres on using the advanced characterisation techniques our lab specialises in, and developing new techniques tailored to multi-junctions, to better understand how these devices operate. Based on this information, we are developing strategies to increase the efficiency and stability of perovskite multi-junctions.
Beyond double-junction tandem solar cells, triple-junction solar cells have an even higher theoretical efficiency, dividing the spectrum into three absorption segments. The key here is to make sure that the currents are well matched between each of the subcells. This depends on the bandgap of the perovskite absorber material, thickness, and any light trapping methods. The fabrication of such devices becomes more complicated as the number of layers involved increases.
Related Publications
- Lang, F. et al., Joule 2020,4.5: 1054-1069;
- Tennyson, E. et al., ACS Energy Lett. 2021, 6, 6, 2293–2304;
- Chiang, Y. et al., ACS Energy Lett. 2023, 8, 6, 2728–2737;
- Fitzsimmons, M. et al., ACS Energy Lett. 2025, 10, 2, 713–725;
- Yang, T. et al., EES Sol., 2025, 1, 41-55.
Evaporated Perovskites
Our research focuses on thermal evaporation as a method for the deposition of perovskite thin films. This solvent-free, industry-compatible technique offers precise nanoscale control over film thickness, excellent scalability to large areas, and compatibility with flexible substrates. By enabling the integration of solvent-sensitive materials into device architectures, thermal evaporation opens up new design strategies to enhance device performance.
Related Publications
1. Chiang, Y. et al., ACS Energy Lett. 2020, 5, 8, 2498–2504;
2. Chiang, Y. et al., ACS Energy Lett. 2023, 8, 6, 2728–2737;
3. Lu, Y. and Jung, Y-K. et al., Science 2025, 390, 716-721.
Narrow Bandgap (Sn-based) Perovskites
Our research is primarily focused on elucidating the influence of material processing techniques on the overall performance of solar devices. While the efficiency of lead (Pb)-based perovskite solar cells has surpassed 27%, the performance of narrow band gap perovskite solar cells, particularly those based on tin (Sn), remains constrained. We seek to gain insights into the intricate mechanisms of charge carrier recombination and transport within these materials while identifying the current limitations of existing material processing methods. Armed with this knowledge, we have proposed innovative strategies to overcome these limitations, such as tuning the doping level.
Related Publications
1. Galkowski, K., et al., ACS Energy Lett. 2019, 4, 3, 615–621;
2. Dey, K. et al., Advanced Materials, 2021, 33(40), 2102300;
3. Senanayak, P., Dey, K. et al., Nature Materials, 2022, 22(2), 216-224.
Photodetectors
Our research leverages the tunable band gap and capabilities of all-perovskite tandem solar cells to introduce a novel device concept, enabling multiband response from a single multijunction device. This device allows for rapid, optically controlled switching between bands, with the goal of achieving highly selective, narrowband, and sensitive photodetection. This advancement opens up numerous possibilities for applications in optical communications, including secure encryption.
Related Publications
1. Moseley, O. et al., ACS Photonics 2022, 9, 12, 3958–3966;
2. Moseley, O. et al., ACS Appl. Energy Mater. 2023, 6, 20, 10233–10242;
3. Ooi, Z. et al., ACS Photonics 2025, 12, 8, 4119–4129.
Solar Fuels
Our work on solar fuels with oxide and carbon semiconductors uses solid-state heterojunctions and earth-abundant catalysts. The research is focused on the anisotropic electronic and photophysics of semiconductors by combining the advanced spectroscopic tools with unique thin-film materialsls.
Related Publications
1. Horizon EU ‘Fuel from the Sun’ Finalists with artificial leaves capable of producing a sustainable solar fuel, with Professor Erwin Reisner’s group: https://www.royce.ac.uk/news/cambridge-research-team-reaches-eu-fuel-from-the-sun-final/
2. Macpherson, S. et, al., Influence of Electron Donors on the Charge Transfer Dynamics of Carbon Nanodots in Photocatalytic Systems. ACS Catal. 2024, 14, 16, 12006–12015
3. Pan, L. and Dai, L. et, al., High carrier mobility along the [111] orientation in Cu2O photoelectrodes. Nature 2024, 628, 765-770.
Defect Passivation Methods
In our research endeavours, we are dedicated to pioneering innovative methodologies aimed at passivating defect states and mitigating materials degradation within the light-absorbing layers of perovskite solar cells. We have employed a diverse array of novel chemicals in both our materials and device fabrication processes. This strategic approach is designed to enhance the operational stability and boost the power conversion efficiency of our solar cells.
Related Publications
1. Brenes, R., et al., Joule, 2017, 1, 155-167;
2. Abdi-Jalebi, M., et al., Nature, 2018, 555, 497-501;
3. Nagane, S., et al., Advanced Materials, 2021, 33, 2102462.
Interface & Charge Transport Engineering
Our research focuses on designing and analysing new interfacial and charge transport layers to enhance carrier extraction and stability in perovskite and hybrid optoelectronic devices. We introduce self-assembled monolayers (SAMs), graphene oxide–based interlayers, dipolar buffer layers, and amphiphilic polymer conetworks (APCNs) to regulate interfacial energetics and suppress nonradiative recombination.
By combining structural, optical, and electronic characterisation, we establish fundamental design principles for efficient charge transport across complex heterojunctions, providing insights into next-generation high-efficiency and stable device architectures.
Related Publications
1. Fitzsimmons, M. et al., ACS Energy Lett. 2025, 10, 2, 713–725;
2. Kim, D. et al., ACS Energy Lett. 2025, 10, 9, 4712–4721;
3. Huang, C.-S. et al., Adv. Energy Mater., 2025, e04273.
Understanding Energy Loss Mechanism in Light-harvesting Applications
The Light Harvesting subgroup works closely with the Spectroscopy and Materials subgroups to apply advanced spectroscopy and multimodal microscopy techniques for understanding loss mechanisms in state-of-the-art light-harvesting devices. This includes operando photoluminescence quantum yield, in-situ hyperspectral microscopy, time-resolved spectroscopy and microscopy, synchrotron-based X-ray micro-spectroscopy & diffraction and high-resolution electron microscopy to investigate how local heterogeneity influences charge accumulation and device degradation. By bridging materials and device engineering with the underlying photophysics and photochemistry of next-generation semiconductors, we aim to provide a comprehensive understanding of performance loss mechanisms in the most efficient light-harvesting devices.
Related Publications
1. T. A. S. Doherty et al., Stabilized tilted-octahedra halide perovskites inhibit local formation of performance-limiting phases, Science, 2021, 374, 6575, 1598–1605
2. Li, S., Xiao Y., Su R., and Xu, W. et al. Coherent growth of high-Miller-index facets enhances perovskite solar cells. Nature 2024, 635(8040), 874–881.
3. Pan, L. and Dai, L. et, al., High carrier mobility along the [111] orientation in Cu2O photoelectrodes. Nature 2024, 628, 765-770.
4. Wang, Y., Lin, R., Liu, C., Wang, X. and Chosy, C. et al. Homogenized contact in all-perovskite tandems using tailored 2D perovskite. Nature 2024, 635, 867–873.
5. Frohna, K. and Chosy, C. et al. The impact of interfacial quality and nanoscale performance disorder on the stability of alloyed perovskite solar cells. Nature Energy 2025, 10(1), 66-76.
6. Xu, W. et al. Unveiling the Role of Guanidinium for Enhanced Charge Extraction in Inverted Perovskite Solar Cells. ACS Energy Lett. 2025, 10(6), 2660–2669.