Limits...
Molecular packing and electronic processes in amorphous-like polymer bulk heterojunction solar cells with fullerene intercalation.

Xiao T, Xu H, Grancini G, Mai J, Petrozza A, Jeng US, Wang Y, Xin X, Lu Y, Choon NS, Xiao H, Ong BS, Lu X, Zhao N - Sci Rep (2014)

Bottom Line: In this work we carried out a systematic investigation on a high PV efficiency (>6%) BHJ system consisting of a newly developed 5,6-difluorobenzo[c] thiadiazole-based copolymer, PFBT-T20TT, and a fullerene derivative.Furthermore, we extracted the hole mobility based on the space limited current (SCLC) model and found that more efficient hole transport is achieved in the PFBT-T20TT:fullerene BHJ as compared to pure PFBT-T20TT, showing a different trend as compared to the previously reported highly crystalline polymer:fullerene blend with a similar intercalation manner.Our study correlates the fullerene intercalated polymer lamella morphology with device performance and provides a coherent model to interpret the high photovoltaic performance of some of the recently developed weakly-ordered BHJ systems based on conjugated polymers with branched side-chain.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Engineering, Chinese University of Hong Kong, New Territories, Hong Kong.

ABSTRACT
The interpenetrating morphology formed by the electron donor and acceptor materials is critical for the performance of polymer:fullerene bulk heterojunction (BHJ) photovoltaic (PV) cells. In this work we carried out a systematic investigation on a high PV efficiency (>6%) BHJ system consisting of a newly developed 5,6-difluorobenzo[c] thiadiazole-based copolymer, PFBT-T20TT, and a fullerene derivative. Grazing incidence X-ray scattering measurements reveal the lower-ordered nature of the BHJ system as well as an intermixing morphology with intercalation of fullerene molecules between the PFBT-T20TT lamella. Steady-state and transient photo-induced absorption spectroscopy reveal ultrafast charge transfer (CT) at the PFBT-T20TT/fullerene interface, indicating that the CT process is no longer limited by exciton diffusion. Furthermore, we extracted the hole mobility based on the space limited current (SCLC) model and found that more efficient hole transport is achieved in the PFBT-T20TT:fullerene BHJ as compared to pure PFBT-T20TT, showing a different trend as compared to the previously reported highly crystalline polymer:fullerene blend with a similar intercalation manner. Our study correlates the fullerene intercalated polymer lamella morphology with device performance and provides a coherent model to interpret the high photovoltaic performance of some of the recently developed weakly-ordered BHJ systems based on conjugated polymers with branched side-chain.

No MeSH data available.


Related in: MedlinePlus

(a) J–V characteristics of PFBT-T20TT:PC71BM BHJ solar cell and the device configuration, (b) the molecular structure of PFBT-T20TT and (c) the schematic figure of the energy level alignments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4048884&req=5

f1: (a) J–V characteristics of PFBT-T20TT:PC71BM BHJ solar cell and the device configuration, (b) the molecular structure of PFBT-T20TT and (c) the schematic figure of the energy level alignments.

Mentions: Figure 1 shows the device information for the PFBT-T20TT:PC71BM (1:2 mass ratio) BHJ PV cells based on a structure of ITO/PEDOT:PSS/PFBT-T20TT:PC71BM/Ca/Al. The current density-voltage (J–V) characteristics of the PV cell are plotted in Figure 1(a), which exhibit an open-circuit voltage (Voc) of 0.82 V, an short-circuit current density (Jsc) of 12.93 mA·cm−2, a fill factor of 61% and an overall PCE of 6.3% under AM 1.5 illumination. Figure 1(b) represents the detailed energy level alignments of the PV cells. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PFBT-T20TT are −5.46 eV and −3.59 eV, respectively. For optimized PFBT-T20TT:PCBM mixing ratio (1:2), all devices show efficiency over 5% (Figure S1, Supplementary Information). Adding more PC71BM loading would lead to lower Jsc and fill factor, thus reducing the PCE (Figure S1, Supplementary Information).


Molecular packing and electronic processes in amorphous-like polymer bulk heterojunction solar cells with fullerene intercalation.

Xiao T, Xu H, Grancini G, Mai J, Petrozza A, Jeng US, Wang Y, Xin X, Lu Y, Choon NS, Xiao H, Ong BS, Lu X, Zhao N - Sci Rep (2014)

(a) J–V characteristics of PFBT-T20TT:PC71BM BHJ solar cell and the device configuration, (b) the molecular structure of PFBT-T20TT and (c) the schematic figure of the energy level alignments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048884&req=5

f1: (a) J–V characteristics of PFBT-T20TT:PC71BM BHJ solar cell and the device configuration, (b) the molecular structure of PFBT-T20TT and (c) the schematic figure of the energy level alignments.
Mentions: Figure 1 shows the device information for the PFBT-T20TT:PC71BM (1:2 mass ratio) BHJ PV cells based on a structure of ITO/PEDOT:PSS/PFBT-T20TT:PC71BM/Ca/Al. The current density-voltage (J–V) characteristics of the PV cell are plotted in Figure 1(a), which exhibit an open-circuit voltage (Voc) of 0.82 V, an short-circuit current density (Jsc) of 12.93 mA·cm−2, a fill factor of 61% and an overall PCE of 6.3% under AM 1.5 illumination. Figure 1(b) represents the detailed energy level alignments of the PV cells. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PFBT-T20TT are −5.46 eV and −3.59 eV, respectively. For optimized PFBT-T20TT:PCBM mixing ratio (1:2), all devices show efficiency over 5% (Figure S1, Supplementary Information). Adding more PC71BM loading would lead to lower Jsc and fill factor, thus reducing the PCE (Figure S1, Supplementary Information).

Bottom Line: In this work we carried out a systematic investigation on a high PV efficiency (>6%) BHJ system consisting of a newly developed 5,6-difluorobenzo[c] thiadiazole-based copolymer, PFBT-T20TT, and a fullerene derivative.Furthermore, we extracted the hole mobility based on the space limited current (SCLC) model and found that more efficient hole transport is achieved in the PFBT-T20TT:fullerene BHJ as compared to pure PFBT-T20TT, showing a different trend as compared to the previously reported highly crystalline polymer:fullerene blend with a similar intercalation manner.Our study correlates the fullerene intercalated polymer lamella morphology with device performance and provides a coherent model to interpret the high photovoltaic performance of some of the recently developed weakly-ordered BHJ systems based on conjugated polymers with branched side-chain.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronic Engineering, Chinese University of Hong Kong, New Territories, Hong Kong.

ABSTRACT
The interpenetrating morphology formed by the electron donor and acceptor materials is critical for the performance of polymer:fullerene bulk heterojunction (BHJ) photovoltaic (PV) cells. In this work we carried out a systematic investigation on a high PV efficiency (>6%) BHJ system consisting of a newly developed 5,6-difluorobenzo[c] thiadiazole-based copolymer, PFBT-T20TT, and a fullerene derivative. Grazing incidence X-ray scattering measurements reveal the lower-ordered nature of the BHJ system as well as an intermixing morphology with intercalation of fullerene molecules between the PFBT-T20TT lamella. Steady-state and transient photo-induced absorption spectroscopy reveal ultrafast charge transfer (CT) at the PFBT-T20TT/fullerene interface, indicating that the CT process is no longer limited by exciton diffusion. Furthermore, we extracted the hole mobility based on the space limited current (SCLC) model and found that more efficient hole transport is achieved in the PFBT-T20TT:fullerene BHJ as compared to pure PFBT-T20TT, showing a different trend as compared to the previously reported highly crystalline polymer:fullerene blend with a similar intercalation manner. Our study correlates the fullerene intercalated polymer lamella morphology with device performance and provides a coherent model to interpret the high photovoltaic performance of some of the recently developed weakly-ordered BHJ systems based on conjugated polymers with branched side-chain.

No MeSH data available.


Related in: MedlinePlus