Alexandros Stavrinadis profile

Summary

I enjoy developing and understanding new materials that can improve existing technologies and create new ones. My current research is focused on semiconductor nanomaterials and thin films for optoelectronic applications like solar cells.

I work on the synthesis and characterization of inorganic semiconductor and metallic thin films and nanoparticles. I use nanomaterials to make solar cells (photovoltaics) and other type of devices like thin film transistors (FETs) and photodetectors. Ultimately, I measure the efficiency and various optical and electronic properties of those devices and use the results as feedback to to innovate on and improve the conditions used during material growth and processing.

Some material and thin film fabrication techniques I apply in my research are:
-Physical Vapor Deposition (PVD) e.g. sputtering, thermal evaporation)
-Thermal annealing processes i.e. rapid thermal annealing (RTP)
-Colloidal synthesis of nanoparticles and quantum dots i.e. hot injection method
-Sol-Gel i.e. for fabrication of oxide thin films

In my work I use a number of material characterization techniques like
-TEM, HREM, SAED, XRD, XPS, UPS, FT-IR, Raman, TGA, SEM, FIB, EDX, UV-Vis, PL, Cyclic Voltammetry

Some of the most common optoelectronic measurements and analysis methods I utilize for understanding the physics of my semiconductor materials and devices are:
-J-V characteristics under solar light
-External quantum efficiency (EQE) measurements at short circuit and applied bias conditions
-C-V characteristics and Mott-Schottky analysis
-Transient photo- voltage and current (TPV, TPC) measurements
-Stress and aging test of solar cells under various environmental conditions

Some types of materials I am very familiar with are:
-Quantum dots (e.g. PbS, CdS, PbSe)
-Semiconductor Nanoparticles (e.g. Bi2S3, SnS)
-Wide bandgap semiconductor films (e.g. ZnO, Ti2O)
-Semiconductor polymers (e.g. P3HT, MEH-PPV).

Work Experience (1)

ICFO NEST Fellow

ICFO

January 2013 - Present

Barcelona Area, Spain

This position was associated with the ICFO-NEST postdoctoral fellowship award I received for developing my own research project on achieving controlled and robust electronic doping of colloidal quantum dots for optoelectronics.

In that project, I developed a new scheme for doping of PbS colloidal quantum dots with aliovalent ions, primarily trivalent cations like Bi3+ and Sb3+. I further demonstrated that, upon substituting Pb2+, the aforementioned cations act as n-dopants, thus changing the semiconductor character of the PbS dots from being p-type to becoming n-type. I then utilized that achievement for making some quantum dot p-n homojunctions that also operate as very robust photovoltaic cells under normal atmospheric conditions; these were the first of their kind.
My respective research resulted to three research papers published in high impact journals like Nature Communications and Scientific Reports and led to several collaborations with external academic groups interested in my doped materials and devices.

Some more specific experimental activities/techniques I was engaged with during that project are:
-synthesis and modification of QDs (hot injection method, cation/ligand exchange reactions)
-characterization (TEM, XPS, UPS< SEM, EDX, FIB, FTIR, Raman, Uv-Vis, PL etc.)
-thin film and device fabrication (spin coating, solgel, thermal evaporation, etc.)
-optoelectronic testing of devices(JV, EQE, C-V, etc.)