PAL RESEARCH GROUP
Welcome to Pal Research Group
RESEARCH
Exciton dynamics in quantum dots (QDs) and multiple exciton generation
In QDs the energy of an absorbed photon can via multiple exciton generation (MEG) be broken down into many electron-hole pairs thereby increasing the photocurrent. Alternatively, hot electron transfer can use the extra energy providing higher photovoltage. Both of these processes are capable of improving the solar cell efficiency beyond the Shockley-Queisser limit. In order to make use of the effects, the processes have to be followed by efficient charge stabilization with minimal back recombination. It is also vital to efficiently fill the holes left in QDs after electron injection. The purpose of the current project is to carry out a thorough study of the dynamic processes in the material to optimize the key components of QD solar cells (QDSC).
Graphene in optoelectronics
Tuning of optical and electronic properties of graphene via structure modification is very useful for the optoelectronic applications of graphene. Band positions and hence bandgap of graphene can be modified via oxidation and functionalization. Herein, our focus is to study the properties of physically and chemically modified graphene in order to utilize them in organic solar cells. The electrical properties of modified graphene are investigated with the aim to use them in optoelectronic devices as transparent electrode.
Spectroscopy of organic and organic-inorganic hybrid materials
Organic materials exhibit photophysical properties that are useful for optoelectronic and light harvesting applications. Nevertheless, inorganic nanomaterials possess interesting optical and electrical properties depending on their size/shape and those properties can be tuned by chemical synthesis. Inorganic nanomaterials could enhancing the performance of organic material based optoelectronic devices. In this project photoinduced processes like fluorescence, phosphorescence, energy and electron transfer in organic-inorganic nanomaterial combinations are investigated using the steady state and time-resolved spectroscopic techniques. The outcome of this project will have great impact on the course of development of organic optoelectronic devices.
Organic Photovoltaics: materials and devices
One of the major concerns about organic solar cells is their low efficiency. Recent studies have pointed out that poor absorption and low carrier mobility of organic materials are responsible for the limited performance of organic photovoltaic cells. Molecular orbital mismatch that governs the open circuit voltage is also an important factor. Therefore, synthesis of novel organic materials (polymers and small molecules), develop new device architectures, spectroscopic investigation on materials and electrical characterization of devices are some of the aims of this project to address the efficiency issue.
Calculations on surfaces and nanostructured materials
Ab initio calculations are performed on nanostructured materials (oxidenanomaterials, graphene sheets etc.) to study the binding possibility of organic molecules onto them. Quantum chemical calculations are used to investigate fundamental structural and electronic properties of nanostructured materials, with particular focus on using them in third generation solar cells.