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Power generating reflective-type liquid crystal displays using a reflective polariser and a polymer solar cell.

Ho Huh Y, Park B - Sci Rep (2015)

Bottom Line: We herein report the results of a study of a power generating reflective-type liquid crystal display (LCD), composed of a 90° twisted nematic (TN) LC cell attached to the top of a light-absorbing polymer solar cell (PSC), i.e., a Solar-LCD.The Solar-LCD also exhibited a significantly improved contrast ratio of more than 17-19.We believe there is a clear case for using such Solar-LCDs in new power-generating reflective-type displays; taken as a whole these results also demonstrate the possibility of their application in a number of energy-harvesting opto-electrical display devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrophysics, Kwangwoon Univ., Wolgye-Dong, Nowon-gu, Seoul 139-701, Korea.

ABSTRACT
We herein report the results of a study of a power generating reflective-type liquid crystal display (LCD), composed of a 90° twisted nematic (TN) LC cell attached to the top of a light-absorbing polymer solar cell (PSC), i.e., a Solar-LCD. The PSC consisted of a polymer bulk-heterojunction photovoltaic (PV) layer of poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] and [6,6]-phenyl C71 butyric acid methyl ester (PCDTBT:PCBM70), and showed a high power conversion efficiency of about 5%. In order to improve the visibility of the Solar-LCD, between the TN-LC and the PV cells we inserted a reflective polariser of a giant birefringent optical (GBO) film. The reflectivity from the Solar-LCD was observed to be considerably increased by more than 13-15% under illumination by visible light. The Solar-LCD also exhibited a significantly improved contrast ratio of more than 17-19. We believe there is a clear case for using such Solar-LCDs in new power-generating reflective-type displays; taken as a whole these results also demonstrate the possibility of their application in a number of energy-harvesting opto-electrical display devices.

No MeSH data available.


(a) Polarised reflectance spectra of the GBO reflecting polariser for incident light polarised linearly along the passing and reflecting axes. The inset shows the reflected–light photomicrographs at four angles of rotation of the GBO polariser under an optical polarising microscope. The arrows indicate the passing axis (x) of the GBO polariser and the orientation (P) of the polariser of the microscope. (b) Polarised reflectance of the GBO polariser as a function of the rotating angle θ between the polarisation direction of incident light and the passing axis of the GBO polariser for blue (470 nm), green (550 nm) and red (630 nm) lights. (c) Photographs of a pair of flexible polarisers that are partially overlapping, showing an underlying GBO reflecting polariser and an overlying dichroic sheet polariser for parallel (left) and crossed (right) polarisation states. The arrows show the passing axes of the polarisers.
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f2: (a) Polarised reflectance spectra of the GBO reflecting polariser for incident light polarised linearly along the passing and reflecting axes. The inset shows the reflected–light photomicrographs at four angles of rotation of the GBO polariser under an optical polarising microscope. The arrows indicate the passing axis (x) of the GBO polariser and the orientation (P) of the polariser of the microscope. (b) Polarised reflectance of the GBO polariser as a function of the rotating angle θ between the polarisation direction of incident light and the passing axis of the GBO polariser for blue (470 nm), green (550 nm) and red (630 nm) lights. (c) Photographs of a pair of flexible polarisers that are partially overlapping, showing an underlying GBO reflecting polariser and an overlying dichroic sheet polariser for parallel (left) and crossed (right) polarisation states. The arrows show the passing axes of the polarisers.

Mentions: We used a GBO polarising film as the reflective polariser in the Solar-LCDs. The polarised reflectance spectra from the GBO reflecting polariser were then observed for the two incident light beams polarised linearly along the passing and reflecting axes, both of which are shown in Fig. 2(a). From the figure, it is clear that the nature of the reflection bands depends strongly on the polarisation of the incident light; when measured in the direction of the reflecting axis, the reflection spectrum shows a strong and broad reflection band, while in the direction of the passing axis, there is virtually no reflection band in the wide visible wavelength range (400 ~ 800 nm) that includes blue (B), green (G), and red (R) lights. The average extinction ratio of the GBO reflective polariser used was estimated to be about 60:1 for wavelengths between 450 and 750 nm. The polarised reflection from the GBO polariser can be seen in the reflective microphotograph of the polariser obtained under polarised incident light for four angles of rotation of the GBO polariser (Inset in Fig. 2(a)). This figure confirms that the GBO film used causes a clear polarised reflection of light. The two darker views of the reflective microphotographs enable us to obtain the orientations of the optic axes for the GBO reflecting polariser. Figure 2(b) shows a graph of the polarised reflectance of the GBO reflecting polariser as a function of the azimuth rotation angle θ between the passing axis of the GBO polariser and the polarisation of the incident light for B (470 nm), G (550 nm), and R (630 nm) lights at normal incidence. As shown in the figure, the reflectance R is clearly governed by the relationship R = A cos2(90°−θ), where A is the polarised reflectance for incident light polarised linearly along the reflecting axes.


Power generating reflective-type liquid crystal displays using a reflective polariser and a polymer solar cell.

Ho Huh Y, Park B - Sci Rep (2015)

(a) Polarised reflectance spectra of the GBO reflecting polariser for incident light polarised linearly along the passing and reflecting axes. The inset shows the reflected–light photomicrographs at four angles of rotation of the GBO polariser under an optical polarising microscope. The arrows indicate the passing axis (x) of the GBO polariser and the orientation (P) of the polariser of the microscope. (b) Polarised reflectance of the GBO polariser as a function of the rotating angle θ between the polarisation direction of incident light and the passing axis of the GBO polariser for blue (470 nm), green (550 nm) and red (630 nm) lights. (c) Photographs of a pair of flexible polarisers that are partially overlapping, showing an underlying GBO reflecting polariser and an overlying dichroic sheet polariser for parallel (left) and crossed (right) polarisation states. The arrows show the passing axes of the polarisers.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
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f2: (a) Polarised reflectance spectra of the GBO reflecting polariser for incident light polarised linearly along the passing and reflecting axes. The inset shows the reflected–light photomicrographs at four angles of rotation of the GBO polariser under an optical polarising microscope. The arrows indicate the passing axis (x) of the GBO polariser and the orientation (P) of the polariser of the microscope. (b) Polarised reflectance of the GBO polariser as a function of the rotating angle θ between the polarisation direction of incident light and the passing axis of the GBO polariser for blue (470 nm), green (550 nm) and red (630 nm) lights. (c) Photographs of a pair of flexible polarisers that are partially overlapping, showing an underlying GBO reflecting polariser and an overlying dichroic sheet polariser for parallel (left) and crossed (right) polarisation states. The arrows show the passing axes of the polarisers.
Mentions: We used a GBO polarising film as the reflective polariser in the Solar-LCDs. The polarised reflectance spectra from the GBO reflecting polariser were then observed for the two incident light beams polarised linearly along the passing and reflecting axes, both of which are shown in Fig. 2(a). From the figure, it is clear that the nature of the reflection bands depends strongly on the polarisation of the incident light; when measured in the direction of the reflecting axis, the reflection spectrum shows a strong and broad reflection band, while in the direction of the passing axis, there is virtually no reflection band in the wide visible wavelength range (400 ~ 800 nm) that includes blue (B), green (G), and red (R) lights. The average extinction ratio of the GBO reflective polariser used was estimated to be about 60:1 for wavelengths between 450 and 750 nm. The polarised reflection from the GBO polariser can be seen in the reflective microphotograph of the polariser obtained under polarised incident light for four angles of rotation of the GBO polariser (Inset in Fig. 2(a)). This figure confirms that the GBO film used causes a clear polarised reflection of light. The two darker views of the reflective microphotographs enable us to obtain the orientations of the optic axes for the GBO reflecting polariser. Figure 2(b) shows a graph of the polarised reflectance of the GBO reflecting polariser as a function of the azimuth rotation angle θ between the passing axis of the GBO polariser and the polarisation of the incident light for B (470 nm), G (550 nm), and R (630 nm) lights at normal incidence. As shown in the figure, the reflectance R is clearly governed by the relationship R = A cos2(90°−θ), where A is the polarised reflectance for incident light polarised linearly along the reflecting axes.

Bottom Line: We herein report the results of a study of a power generating reflective-type liquid crystal display (LCD), composed of a 90° twisted nematic (TN) LC cell attached to the top of a light-absorbing polymer solar cell (PSC), i.e., a Solar-LCD.The Solar-LCD also exhibited a significantly improved contrast ratio of more than 17-19.We believe there is a clear case for using such Solar-LCDs in new power-generating reflective-type displays; taken as a whole these results also demonstrate the possibility of their application in a number of energy-harvesting opto-electrical display devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrophysics, Kwangwoon Univ., Wolgye-Dong, Nowon-gu, Seoul 139-701, Korea.

ABSTRACT
We herein report the results of a study of a power generating reflective-type liquid crystal display (LCD), composed of a 90° twisted nematic (TN) LC cell attached to the top of a light-absorbing polymer solar cell (PSC), i.e., a Solar-LCD. The PSC consisted of a polymer bulk-heterojunction photovoltaic (PV) layer of poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl] and [6,6]-phenyl C71 butyric acid methyl ester (PCDTBT:PCBM70), and showed a high power conversion efficiency of about 5%. In order to improve the visibility of the Solar-LCD, between the TN-LC and the PV cells we inserted a reflective polariser of a giant birefringent optical (GBO) film. The reflectivity from the Solar-LCD was observed to be considerably increased by more than 13-15% under illumination by visible light. The Solar-LCD also exhibited a significantly improved contrast ratio of more than 17-19. We believe there is a clear case for using such Solar-LCDs in new power-generating reflective-type displays; taken as a whole these results also demonstrate the possibility of their application in a number of energy-harvesting opto-electrical display devices.

No MeSH data available.