Publicação
Colloidal Lithography for Light Trapping in Flexible Thin Film Solar Cells
| Resumo: | The demand for more efficient, reliable, and economical optoelectronic and photovoltaic (PV) devices has led researchers to explore nano/microtechnological solutions. These solu- tions aim to enhance PV performance without significantly increasing production costs. Among these, photonic structures based on wavelength-sized transparent conductive oxides (TCOs) are particularly promising. They improve efficiency by reducing reflection and opti- mizing light absorption inside the solar cells, as well as in other photodetector devices like UV sensors. In this work, we developed a simple, low-cost, versatile, and highly scalable colloidal lithography process to fabricate and optimize three different microstructures: indium zinc ox- ide (IZO), indium tin oxide (ITO), and titanium dioxide (TiO2). These microstructures, with wavelength-sized features, were smoothly modelled on flexible ITO substrates coated with polyethylene terephthalate (PET), parylene C membranes, and rigid substrates (glass) coated with ITO. The ITO micro-mesh demonstrated enhanced transparent electrode properties, showing significant light interaction with a pronounced light scattering performance (diffuse transmission up to ~50%). Additionally, the microstructured photonic mesh of TCOs allowed for a greater volume of material in the electrode while maintaining desired transparency, lead- ing to a reduction in sheet resistance (~14%) and improved electrical benefits due to enhanced contact conductance. When integrated into perovskite solar cell test devices, these microstruc- tured photonic meshes provided excellent optical improvements, yielding short-circuit pho- tocurrent gains of up to ~20% and efficiency gains of up to ~17%, closely matching the values predicted by modelling optimizations. In view of exploring other promising applications, the microstructuring of test parylene- C membranes was investigated in UV sensors. This resulted in a pronouncedly enhanced pho- tocurrent response when compared with non-structured devices. These findings pave the way for a new class of transparent photonic electrodes with mechanical flexibility. They hold strong potential not only as advanced front contacts for thin- film foldable solar cells but also for a wide range of optoelectronic applications. |
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| Autores principais: | Boane, Jenny Luis Nhaliguangue |
| Assunto: | Photovoltaics Photonics Colloidal Lithography Transparent Microstructured electrodes UV Sensors |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | The demand for more efficient, reliable, and economical optoelectronic and photovoltaic (PV) devices has led researchers to explore nano/microtechnological solutions. These solu- tions aim to enhance PV performance without significantly increasing production costs. Among these, photonic structures based on wavelength-sized transparent conductive oxides (TCOs) are particularly promising. They improve efficiency by reducing reflection and opti- mizing light absorption inside the solar cells, as well as in other photodetector devices like UV sensors. In this work, we developed a simple, low-cost, versatile, and highly scalable colloidal lithography process to fabricate and optimize three different microstructures: indium zinc ox- ide (IZO), indium tin oxide (ITO), and titanium dioxide (TiO2). These microstructures, with wavelength-sized features, were smoothly modelled on flexible ITO substrates coated with polyethylene terephthalate (PET), parylene C membranes, and rigid substrates (glass) coated with ITO. The ITO micro-mesh demonstrated enhanced transparent electrode properties, showing significant light interaction with a pronounced light scattering performance (diffuse transmission up to ~50%). Additionally, the microstructured photonic mesh of TCOs allowed for a greater volume of material in the electrode while maintaining desired transparency, lead- ing to a reduction in sheet resistance (~14%) and improved electrical benefits due to enhanced contact conductance. When integrated into perovskite solar cell test devices, these microstruc- tured photonic meshes provided excellent optical improvements, yielding short-circuit pho- tocurrent gains of up to ~20% and efficiency gains of up to ~17%, closely matching the values predicted by modelling optimizations. In view of exploring other promising applications, the microstructuring of test parylene- C membranes was investigated in UV sensors. This resulted in a pronouncedly enhanced pho- tocurrent response when compared with non-structured devices. These findings pave the way for a new class of transparent photonic electrodes with mechanical flexibility. They hold strong potential not only as advanced front contacts for thin- film foldable solar cells but also for a wide range of optoelectronic applications. |
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