My current research interests primarily revolve around the development and optimization of thin-film solar cells, CdTe solar cells. I have expertise in various fabrication techniques such as thermal evaporation, CSS, CBD, spray and spin coating, and electrodeposition. Additionally, I explore material characterization using a wide range of techniques, including GIXRD, XRF, XPS, EIS, SEM and UV-visible spectroscopy, among others. My research also extends to device characterization through methods like current-voltage (I-V) measurements and external quantum efficiency (EQE) analysis. Furthermore, I investigate theoretical aspects using simulation tools like SCAPS-1D and Lumerical FDTD.
EDUCATION
PhD in Physics of Materials, University of Peradeniya, Sri Lanka
BSc (Hons) in Physics, University of Jaffna, Sri Lanka
RESEARCH, TEACHING, or OTHER INTERESTS
Physics and Astronomy, Materials Science
10
Scopus Publications
85
Scholar Citations
5
Scholar h-index
2
Scholar i10-index
Scopus Publications
Enhancing CdS/CdTe thin-film solar cell efficiency: The role of oxygenation in close-spaced sublimated CdS layers K.M.N.S. Bandara, A.A.I. Lakmal, H.C.S. Perera, M.A.K.L. Dissanayake, V.A. Seneviratne, Thomas Delclos, B.S. Dassanayake, Gobind Das Applied Surface Science Advances, 2026 Polycrystalline CdTe photovoltaics are promising alternatives to silicon-based solar cells, with device performance strongly influenced by the n-type CdS window layer. Close-spaced sublimation (CSS) efficiently deposits CdS layers, enabling full device fabrication. In this study, we present a comprehensive investigation into the impact of oxygenation over a wide range of concentrations (0% - 30%) on close-spaced sublimated CdS (CSS-CdS:O) films - an aspect which has not been reported previously. The close-spaced sublimated CdTe (CSS-CdTe) was used as the photon-absorbing layer. Furthermore, it examines the consequent effects on CSS-CdS:O/CSS-CdTe solar cell parameters. Material properties were characterized by means of UV–visible spectroscopy (UV–Vis), Field Emission Scanning Electron Microscope (FE-SEM), and X-ray Photoelectron Spectroscopy (XPS), while a solar simulator was utilized for device characterization. The optimized CdS:O layer with 20% oxygen incorporation yielded the best power conversion efficiency of 9.2%, representing around a 70% increment compared to the oxygen-free sample. The CdS/CdTe device exhibited an open-circuit voltage ( V OC ) of 0.678 V, short circuit current ( J SC ) of 24.8 mA cm - ², and fill factor ( FF ) of 55% under the AM 1.5 G illumination.
Effect of Source Temperature on CSS-deposited CdS Films in Ar for CdS/CdTe Solar Cells: A Combined Experimental and Simulative Study K. M. N. S. Bandara, A. A. I. Lakmal, G. K. U. P. Gajanayake, M. A. K. L. Dissanayake, V. A. Seneviratne, et al. Ceylon Journal of Science, 2026 This study presents a comprehensive investigation into the synthesis and characterization of cadmium sulfide (CdS) window layers for CdS/CdTe thin-film solar cells fabricated using the closed-space sublimation (CSS) method. The work focuses on optimizing the source temperature during CSS deposition under an Ar atmosphere as a cost-effective alternative to the commonly used He atmosphere. By systematically varying the source temperature, the study elucidates the growth behavior of CdS layers in an Ar environment and its influence on the performance of CdS/CdTe solar cells. The as-deposited CdS films were characterized in terms of their optical, morphological, and electrical properties. An optimal source temperature of 660 °C was identified, at which a small-area (0.12 cm²) dot solar cell achieved a power conversion efficiency of 5.7%, an open-circuit voltage (Voc) of 630.5 mV, a short-circuit current density (Jsc) of 17.8 mA cm⁻², and a fill factor (FF) of 51%. Under these conditions, the external quantum efficiency (EQE) reached a maximum value of 70%. SCAPS-1D (Solar Cell Capacitance Simulator) simulations were performed to further validate the experimental results.
Enhancement of solar cell efficiency through tailored electrodeposited seed layers and CdS: O surface texturing A. A. I. Lakmal, H. C.S. Perera, K.M.N.S. Bandara, V. A. Seneviratne, T. Delclos, M. I. Helal, B. S. Dassanayake, G. Das Scientific Reports, 2025 This study focuses on a surface texturing technique using electrodeposition to enhance the junction properties of thin film solar cell structures. The CdS/CdTe solar cell structure was used to demonstrate this concept, focusing on the thermally evaporated oxygenated CdS layer deposition on the textured layer of electrodeposited CdS seeds, ultimately improving the CdS/CdTe junction properties and solar cell performance. Deposited CdS seeds have grown after the deposition of the thermally evaporated CdS: O layer and subsequent annealing. Optical characterizations of CdS seed layers and subsequent CdS layer stacks revealed that seed layers deposited with an applied potential of -680 mV exhibit a significant blue shift and a steep band edge. These optical characteristics were confirmed by the calculated bandgap values. Morphological characterizations exhibited an increment of seed density with applied potential. Additionally, an improved seed size and seed growth upon layer deposition by thermal evaporation were observed for the seeds deposited at -680 mV. Structural characterizations of seed layers via X-ray diffraction followed by Rietveld and Pawley refinements confirmed the optical bandgap variation. X-ray photoelectron spectroscopy validated the results obtained for the optical bandgap with the analysis of surface chemistry of seed layers. These optimized CdS seed layers facilitated subsequent thermal evaporation of CdS: O thin films and the fabrication of CdS/CdTe solar cells. The electrical characterizations emphasized that the solar cells deposited using the seed layer at -680 mV yield better electrical properties.
Thermally Evaporated Copper Iodide Hole-Transporter for Stable CdS/CdTe Thin-Film Solar Cells Thuraisamykurukkal Thivakarasarma, Adikari Arachchige Isuru Lakmal, Buddhika Senarath Dassanayake, Dhayalan Velauthapillai, Punniamoorthy Ravirajan Nanomaterials, 2022 This study focuses on fabricating efficient CdS/CdTe thin-film solar cells with thermally evaporated cuprous iodide (CuI) as hole-transporting material (HTM) by replacing Cu back contact in conventional CdS/CdTe solar cells to avoid Cu diffusion. In this study, a simple thermal evaporation method was used for the CuI deposition. The current-voltage characteristic of devices with CuI films of thickness 5 nm to 30 nm was examined under illuminations of 100 mW/cm2 (1 sun) with an Air Mass (AM) of 1.5 filter. A CdS/CdTe solar cell device with thermally evaporated CuI/Au showed power conversion efficiency (PCE) of 6.92% with JSC, VOC, and FF of 21.98 mA/cm2, 0.64 V, and 0.49 under optimized fabrication conditions. Moreover, stability studies show that fabricated CdS/CdTe thin-film solar cells with CuI hole-transporters have better stability than CdS/CdTe thin-film solar cells with Cu/Au back contacts. The significant increase in FF and, hence, PCE, and the stability of CdS/CdTe solar cells with CuI, reveals that Cu diffusion could be avoided by replacing Cu with CuI, which provides good band alignment with CdTe, as confirmed by XPS. Such an electronic band structure alignment allows smooth hole transport from CdTe to CuI, which acts as an electron reflector. Hence, CuI is a promising alternative stable hole-transporter for CdS/CdTe thin-film solar cells that increases the PCE and stability.
Enhancing CdS/CdTe thin-film solar cell efficiency: The role of oxygenation in close-spaced sublimated CdS layers K Bandara, AAI Lakmal, HCS Perera, M Dissanayake, VA Seneviratne, ... Applied Surface Science Advances 32, 100958 , 2026 2026
Effect of source temperature on CSS-deposited CdS films in Ar for CdS/CdTe solar cells: A combined experimental and simulative study K Bandara, AAI Lakmal, G Gajanayake, M Dissanayake, VA Seneviratne, ... Ceylon Journal of Science 55 (1) , 2026 2026
Enhancement of solar cell efficiency through tailored electrodeposited seed layers and CdS: O surface texturing AAI Lakmal, HCS Perera, K Bandara, VA Seneviratne, T Delclos, MI Helal, ... Scientific Reports 15 (1), 36684 , 2025 2025 Citations: 3
Chemical bath deposited ZnO nanowires for gas sensing: Effect of deposition duration YK Abeykoon, AAI Lakmal, M Munasinghe, BS Dassanayake, ... Journal of Materials Research 39 (3), 367-376 , 2024 2024 Citations: 1
Medium-vacuum thermal evaporation of cds: o thin films towards industrial CdS/CdTe solar cells: temperature and O2% optimization AAI Lakmal, K Bandara, VA Seneviratne, BS Dassanayake Optik 294, 171476 , 2023 2023 Citations: 6
Investigation of the Role of Oxygen in Close-Spaced Sublimated CdS Layer for Enhancing the Efficiency of CdS/CdTe Thin Film Solar Cells BSD KMNS Bandara, AAI Lakmal, VA Seneviratne, MAKL Dissanayake Peradeniya University International Research Sessions (iPURSE 2023) 24, 187 , 2023 2023
Impact of bath temperature on optical and morphological properties of chemical bath deposited CuO thin films BSD RWMK Heenatikumbura, AAI Lakmal Peradeniya University International Research Sessions (iPURSE 2023) 24, 189 , 2023 2023
A review on the Improvisation of Fill Factor in CdS/CdTe Solar Cells AAI Lakmal, G Gajanayake, VA Seneviratne, DSM De Silva, ... Sri Lankan Journal of Applied Sciences 1 (02), 18-26 , 2023 2023
Effect of CdTe nucleation layer on the performance of CdS/CdTe thin film solar cells G Gajanayake, AAI Lakmal, DSM De Silva, BS Dassanayake Journal of Materials Science: Materials in Electronics 34 (6), 508 , 2023 2023 Citations: 13
Optimization of seed layer thickness for the growth of the one dimensional vertically oriented ZnO nanowires YK Abeykoon, AAI Lakmal, M Munasinghe, BS Dassanayake, ... Journal of Materials Science: Materials in Electronics 34 (5), 352 , 2023 2023 Citations: 4
Optik-International Journal for Light and Electron Optics AAI Lakmal, K Bandara, VA Seneviratne, BS Dassanayake Optik-International Journal for Light and Electron Optics 294, 171476 , 2023 2023
Closed space sublimated CdS thin films for CdS/CdTe solar cells: Effect of CdS layer thickness BSD KMNS Bandara, AAI Lakmal, VA Seneviratne, MAKL Dissanayake Postgraduate Institute of Science Research Congress (RESCON-2022 … , 2022 2022
Thermally evaporated copper iodide hole-transporter for stable cds/cdte thin-film solar cells T Thivakarasarma, AAI Lakmal, BS Dassanayake, D Velauthapillai, ... Nanomaterials 12 (14), 2507 , 2022 2022 Citations: 8
Effect of CdS layer thickness on thermally evaporated-CdS/CdTe solar cell efficiency AAI Lakmal, R Kumarasinghe, VA Seneviratne, M Thanihaichelvan, ... Journal of Materials Science: Materials in Electronics 33 (19), 15627-15637 , 2022 2022 Citations: 9
Chemical Bath Deposited CdS Along with Electrodeposited and Closed Space Sublimated CdTe for Solar Cell Fabrication G Gajanayake, AAI Lakmal, DSM De Silva, BS Dassanayake Renewable Energy and Storage Devices for Sustainable Development: Select … , 2022 2022
Chemical Bath Deposited ZnO Nanowires for H2 Gas Sensors: Optimisation of Deposition Time YK Abeykoon, AAI Lakmal, M Munasinghe, BS Dassanayake, ... SLTC Research University Sri Lanka , 2022 2022
Closed space sublimated 𝐂dS thin films for 𝐂dS/𝐂dTe solar cells: Effect of source temperature K Bandara, AAI Lakmal, VA Seneviratne, M Dissanayake, ... University of Jaffna , 2022 2022
Optimization of processing temperature of medium vacuum thermally evaporated 𝐂dS thin-films for 𝐂dTe solar cells AAI Lakmal, K Bandara, VA Seneviratne, BS Dassanayake University of Jaffna , 2022 2022
Thermally evaporated CdS thin films for CdS/CdTe solar cells: Effect of substrate temperature on CdS layer AAI Lakmal, R Kumarasinghe, VA Seneviratne, JY Chen, JM Song, ... Materials Science and Engineering: B 273, 115406 , 2021 2021 Citations: 41
MOST CITED SCHOLAR PUBLICATIONS
Thermally evaporated CdS thin films for CdS/CdTe solar cells: Effect of substrate temperature on CdS layer AAI Lakmal, R Kumarasinghe, VA Seneviratne, JY Chen, JM Song, ... Materials Science and Engineering: B 273, 115406 , 2021 2021 Citations: 41
Effect of CdTe nucleation layer on the performance of CdS/CdTe thin film solar cells G Gajanayake, AAI Lakmal, DSM De Silva, BS Dassanayake Journal of Materials Science: Materials in Electronics 34 (6), 508 , 2023 2023 Citations: 13
Effect of CdS layer thickness on thermally evaporated-CdS/CdTe solar cell efficiency AAI Lakmal, R Kumarasinghe, VA Seneviratne, M Thanihaichelvan, ... Journal of Materials Science: Materials in Electronics 33 (19), 15627-15637 , 2022 2022 Citations: 9
Thermally evaporated copper iodide hole-transporter for stable cds/cdte thin-film solar cells T Thivakarasarma, AAI Lakmal, BS Dassanayake, D Velauthapillai, ... Nanomaterials 12 (14), 2507 , 2022 2022 Citations: 8
Medium-vacuum thermal evaporation of cds: o thin films towards industrial CdS/CdTe solar cells: temperature and O2% optimization AAI Lakmal, K Bandara, VA Seneviratne, BS Dassanayake Optik 294, 171476 , 2023 2023 Citations: 6
Optimization of seed layer thickness for the growth of the one dimensional vertically oriented ZnO nanowires YK Abeykoon, AAI Lakmal, M Munasinghe, BS Dassanayake, ... Journal of Materials Science: Materials in Electronics 34 (5), 352 , 2023 2023 Citations: 4
Enhancement of solar cell efficiency through tailored electrodeposited seed layers and CdS: O surface texturing AAI Lakmal, HCS Perera, K Bandara, VA Seneviratne, T Delclos, MI Helal, ... Scientific Reports 15 (1), 36684 , 2025 2025 Citations: 3
Chemical bath deposited ZnO nanowires for gas sensing: Effect of deposition duration YK Abeykoon, AAI Lakmal, M Munasinghe, BS Dassanayake, ... Journal of Materials Research 39 (3), 367-376 , 2024 2024 Citations: 1
Enhancing CdS/CdTe thin-film solar cell efficiency: The role of oxygenation in close-spaced sublimated CdS layers K Bandara, AAI Lakmal, HCS Perera, M Dissanayake, VA Seneviratne, ... Applied Surface Science Advances 32, 100958 , 2026 2026
Effect of source temperature on CSS-deposited CdS films in Ar for CdS/CdTe solar cells: A combined experimental and simulative study K Bandara, AAI Lakmal, G Gajanayake, M Dissanayake, VA Seneviratne, ... Ceylon Journal of Science 55 (1) , 2026 2026
Investigation of the Role of Oxygen in Close-Spaced Sublimated CdS Layer for Enhancing the Efficiency of CdS/CdTe Thin Film Solar Cells BSD KMNS Bandara, AAI Lakmal, VA Seneviratne, MAKL Dissanayake Peradeniya University International Research Sessions (iPURSE 2023) 24, 187 , 2023 2023
Impact of bath temperature on optical and morphological properties of chemical bath deposited CuO thin films BSD RWMK Heenatikumbura, AAI Lakmal Peradeniya University International Research Sessions (iPURSE 2023) 24, 189 , 2023 2023
A review on the Improvisation of Fill Factor in CdS/CdTe Solar Cells AAI Lakmal, G Gajanayake, VA Seneviratne, DSM De Silva, ... Sri Lankan Journal of Applied Sciences 1 (02), 18-26 , 2023 2023
Optik-International Journal for Light and Electron Optics AAI Lakmal, K Bandara, VA Seneviratne, BS Dassanayake Optik-International Journal for Light and Electron Optics 294, 171476 , 2023 2023
Closed space sublimated CdS thin films for CdS/CdTe solar cells: Effect of CdS layer thickness BSD KMNS Bandara, AAI Lakmal, VA Seneviratne, MAKL Dissanayake Postgraduate Institute of Science Research Congress (RESCON-2022 … , 2022 2022
Chemical Bath Deposited CdS Along with Electrodeposited and Closed Space Sublimated CdTe for Solar Cell Fabrication G Gajanayake, AAI Lakmal, DSM De Silva, BS Dassanayake Renewable Energy and Storage Devices for Sustainable Development: Select … , 2022 2022
Chemical Bath Deposited ZnO Nanowires for H2 Gas Sensors: Optimisation of Deposition Time YK Abeykoon, AAI Lakmal, M Munasinghe, BS Dassanayake, ... SLTC Research University Sri Lanka , 2022 2022
Closed space sublimated 𝐂dS thin films for 𝐂dS/𝐂dTe solar cells: Effect of source temperature K Bandara, AAI Lakmal, VA Seneviratne, M Dissanayake, ... University of Jaffna , 2022 2022
Optimization of processing temperature of medium vacuum thermally evaporated 𝐂dS thin-films for 𝐂dTe solar cells AAI Lakmal, K Bandara, VA Seneviratne, BS Dassanayake University of Jaffna , 2022 2022
RESEARCH OUTPUTS (PATENTS, SOFTWARE, PUBLICATIONS, PRODUCTS)
10W prototype CdS/CdTe solar panel was developed with the collaboration of four universities.
INDUSTRY EXPERIENCE
Quality Control Technician – PVC Industry
S-Lon Lanka (PVT) Ltd., Sandalankawa, Sri Lanka
• Conducted on-production-line tests (dimension measurement) and off-production-line tests (raw material decomposition, mechanical and chemical stability).
• Acquired experience in PVC injection molding and extrusion.
• Developed skills in First Aid and Fire extinguishers.
• Demonstrated proficiency in working with various standards (SLS and ISO).
