sadhon chanda | World University of Bangladesh (original) (raw)

Papers by sadhon chanda

Research paper thumbnail of Conjugated Polymer-Based Organic Solar Cells

Chemical Reviews, Jan 1, 2007

Research paper thumbnail of Nanowire dye-sensitized solar cells

Nature Materials, Jan 1, 2005

Th e DSC is currently the most effi cient 2 and stable 3 excitonic photocell. Central to this dev... more Th e DSC is currently the most effi cient 2 and stable 3 excitonic photocell. Central to this device is a thick nanoparticle fi lm that provides a large surface area for the adsorption of lightharvesting molecules. However, nanoparticle DSCs rely on trap-limited diff usion for electron transport, a slow mechanism that can limit device effi ciency, especially at longer wavelengths. Here we introduce a version of the dye-sensitized cell in which the traditional nanoparticle fi lm is replaced by a dense array of oriented, crystalline ZnO nanowires. Th e nanowire anode is synthesized by mild aqueous chemistry and features a surface area up to one-fi ft h as large as a nanoparticle cell. Th e direct electrical pathways provided by the nanowires ensure the rapid collection of carriers generated throughout the device, and a full Sun effi ciency of 1.5% is demonstrated, limited primarily by the surface area of the nanowire array.

Research paper thumbnail of 2.5% efficient organic plastic solar cells

We show that the power conversion efficiency of organic photovoltaic devices based on a conjugate... more We show that the power conversion efficiency of organic photovoltaic devices based on a conjugated polymer/methanofullerene blend is dramatically affected by molecular morphology. By structuring the blend to be a more intimate mixture that contains less phase segregation of ...

Research paper thumbnail of Efficient Tandem Polymer Solar Cells Fabricated by All-Solution Processing

Science, Jan 1, 2007

Tandem solar cells, in which two solar cells with different absorption characteristics are linked... more Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives. A transparent titanium oxide (TiO(x)) layer separates and connects the front cell and the back cell. The TiO(x) layer serves as an electron transport and collecting layer for the first cell and as a stable foundation that enables the fabrication of the second cell to complete the tandem cell architecture. We use an inverted structure with the low band-gap polymer-fullerene composite as the charge-separating layer in the front cell and the high band-gap polymer composite as that in the back cell. Power-conversion efficiencies of more than 6% were achieved at illuminations of 200 milliwatts per square centimeter.

Research paper thumbnail of Plastic Solar Cells

Advanced Functional Materials, Jan 1, 2001

It is intriguing to think of photovoltaic (PV) elements based on thin plastic films. The flexibil... more It is intriguing to think of photovoltaic (PV) elements based on thin plastic films. The flexibility offered through the chemical tai-loring of desired properties, as well as the cheap technology already well developed for all kinds of plastic thin film applica-tions would make such an ...

Research paper thumbnail of High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends

Nature Materials, Jan 1, 2005

Converting solar energy into electricity provides a much-needed solution to the energy crisis the... more Converting solar energy into electricity provides a much-needed solution to the energy crisis the world is facing today. Polymer solar cells have shown potential to harness solar energy in a cost-effective way. Significant efforts are underway to improve their efficiency to the level of practical applications. Here, we report highly efficient polymer solar cells based on a bulk heterojunction of polymer poly(3-hexylthiophene) and methanofullerene. Controlling the active layer growth rate results in an increased hole mobility and balanced charge transport. Together with increased absorption in the active layer, this results in much-improved device performance, particularly in external quantum efficiency. The power-conversion efficiency of 4.4% achieved here is the highest published so far for polymer-based solar cells. The solution process involved ensures that the fabrication cost remains low and the processing is simple. The high efficiency achieved in this work brings these devices one step closer to commercialization.

Research paper thumbnail of Fundamentals of solar cells

This text is addressed to upper level graduate students with background in solid state physics an... more This text is addressed to upper level graduate students with background in solid state physics and to scientists and engineers involved in solar cell research. The author aims to present fundamental physical principles rather than the state-of-the-art. Specific devices are used to illustrate ...

Research paper thumbnail of Thermally Stable, Efficient Polymer Solar Cells with Nanoscale Control of the Interpenetrating Network Morphology

Advanced Functional Materials, Jan 1, 2005

Research paper thumbnail of Hybrid Nanorod-Polymer Solar Cells

Science, Jan 1, 2002

We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficie... more We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers. By controlling nanorod length, we can change the distance on which electrons are transported directly through the thin film device. Tuning the band gap by altering the nanorod radius enabled us to optimize the overlap between the absorption spectrum of the cell and the solar emission spectrum. A photovoltaic device consisting of 7-nanometer by 60-nanometer CdSe nanorods and the conjugated polymer poly-3(hexylthiophene) was assembled from solution with an external quantum efficiency of over 54% and a monochromatic power conversion efficiency of 6.9% under 0.1 milliwatt per square centimeter illumination at 515 nanometers. Under Air Mass (A.M.) 1.5 Global solar conditions, we obtained a power conversion efficiency of 1.7%.

Research paper thumbnail of A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films

Nature, Jan 1, 1991

THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive... more THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods 1 . Here we describe a photovoltaic cell, created from low-to medium-purity ...

Research paper thumbnail of Conjugated Polymer-Based Organic Solar Cells

Chemical Reviews, Jan 1, 2007

Research paper thumbnail of Nanowire dye-sensitized solar cells

Nature Materials, Jan 1, 2005

Th e DSC is currently the most effi cient 2 and stable 3 excitonic photocell. Central to this dev... more Th e DSC is currently the most effi cient 2 and stable 3 excitonic photocell. Central to this device is a thick nanoparticle fi lm that provides a large surface area for the adsorption of lightharvesting molecules. However, nanoparticle DSCs rely on trap-limited diff usion for electron transport, a slow mechanism that can limit device effi ciency, especially at longer wavelengths. Here we introduce a version of the dye-sensitized cell in which the traditional nanoparticle fi lm is replaced by a dense array of oriented, crystalline ZnO nanowires. Th e nanowire anode is synthesized by mild aqueous chemistry and features a surface area up to one-fi ft h as large as a nanoparticle cell. Th e direct electrical pathways provided by the nanowires ensure the rapid collection of carriers generated throughout the device, and a full Sun effi ciency of 1.5% is demonstrated, limited primarily by the surface area of the nanowire array.

Research paper thumbnail of 2.5% efficient organic plastic solar cells

We show that the power conversion efficiency of organic photovoltaic devices based on a conjugate... more We show that the power conversion efficiency of organic photovoltaic devices based on a conjugated polymer/methanofullerene blend is dramatically affected by molecular morphology. By structuring the blend to be a more intimate mixture that contains less phase segregation of ...

Research paper thumbnail of Efficient Tandem Polymer Solar Cells Fabricated by All-Solution Processing

Science, Jan 1, 2007

Tandem solar cells, in which two solar cells with different absorption characteristics are linked... more Tandem solar cells, in which two solar cells with different absorption characteristics are linked to use a wider range of the solar spectrum, were fabricated with each layer processed from solution with the use of bulk heterojunction materials comprising semiconducting polymers and fullerene derivatives. A transparent titanium oxide (TiO(x)) layer separates and connects the front cell and the back cell. The TiO(x) layer serves as an electron transport and collecting layer for the first cell and as a stable foundation that enables the fabrication of the second cell to complete the tandem cell architecture. We use an inverted structure with the low band-gap polymer-fullerene composite as the charge-separating layer in the front cell and the high band-gap polymer composite as that in the back cell. Power-conversion efficiencies of more than 6% were achieved at illuminations of 200 milliwatts per square centimeter.

Research paper thumbnail of Plastic Solar Cells

Advanced Functional Materials, Jan 1, 2001

It is intriguing to think of photovoltaic (PV) elements based on thin plastic films. The flexibil... more It is intriguing to think of photovoltaic (PV) elements based on thin plastic films. The flexibility offered through the chemical tai-loring of desired properties, as well as the cheap technology already well developed for all kinds of plastic thin film applica-tions would make such an ...

Research paper thumbnail of High-efficiency solution processable polymer photovoltaic cells by self-organization of polymer blends

Nature Materials, Jan 1, 2005

Converting solar energy into electricity provides a much-needed solution to the energy crisis the... more Converting solar energy into electricity provides a much-needed solution to the energy crisis the world is facing today. Polymer solar cells have shown potential to harness solar energy in a cost-effective way. Significant efforts are underway to improve their efficiency to the level of practical applications. Here, we report highly efficient polymer solar cells based on a bulk heterojunction of polymer poly(3-hexylthiophene) and methanofullerene. Controlling the active layer growth rate results in an increased hole mobility and balanced charge transport. Together with increased absorption in the active layer, this results in much-improved device performance, particularly in external quantum efficiency. The power-conversion efficiency of 4.4% achieved here is the highest published so far for polymer-based solar cells. The solution process involved ensures that the fabrication cost remains low and the processing is simple. The high efficiency achieved in this work brings these devices one step closer to commercialization.

Research paper thumbnail of Fundamentals of solar cells

This text is addressed to upper level graduate students with background in solid state physics an... more This text is addressed to upper level graduate students with background in solid state physics and to scientists and engineers involved in solar cell research. The author aims to present fundamental physical principles rather than the state-of-the-art. Specific devices are used to illustrate ...

Research paper thumbnail of Thermally Stable, Efficient Polymer Solar Cells with Nanoscale Control of the Interpenetrating Network Morphology

Advanced Functional Materials, Jan 1, 2005

Research paper thumbnail of Hybrid Nanorod-Polymer Solar Cells

Science, Jan 1, 2002

We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficie... more We demonstrate that semiconductor nanorods can be used to fabricate readily processed and efficient hybrid solar cells together with polymers. By controlling nanorod length, we can change the distance on which electrons are transported directly through the thin film device. Tuning the band gap by altering the nanorod radius enabled us to optimize the overlap between the absorption spectrum of the cell and the solar emission spectrum. A photovoltaic device consisting of 7-nanometer by 60-nanometer CdSe nanorods and the conjugated polymer poly-3(hexylthiophene) was assembled from solution with an external quantum efficiency of over 54% and a monochromatic power conversion efficiency of 6.9% under 0.1 milliwatt per square centimeter illumination at 515 nanometers. Under Air Mass (A.M.) 1.5 Global solar conditions, we obtained a power conversion efficiency of 1.7%.

Research paper thumbnail of A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films

Nature, Jan 1, 1991

THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive... more THE large-scale use of photovoltaic devices for electricity generation is prohibitively expensive at present: generation from existing commercial devices costs about ten times more than conventional methods 1 . Here we describe a photovoltaic cell, created from low-to medium-purity ...