Sungyong Seo

Decorative power generating panels creating angle insensitive transmissive colors

We present ultra-thin (6 to 31 nm) undoped amorphous silicon/organic hybrid solar cell structure, which can transmit desired color of light. The transmitted colors show great angular tolerance due to the negligible optical phase associated with light propagating in ultra-thin amorphous silicon (a-Si) layers. We achieved the power conversion efficiency of the hybrid cells up to 2 %; and demonstrated that most of the absorbed photons in the undoped a-Si layer contributed to the extracted electric charges due to the suppressed electron-hole recombination in the ultra-thin a-Si layer. We also show the resonance is invariant with respect to the angle of incidence up to ±70° regardless of the polarization of the incident light. Our exploration provides a design to realize energy harvesting colored photovoltaic panels for innovative applications.

Strong Resonance Effect in a Lossy Medium‐Based Optical Cavity for Angle Robust Spectrum Filters

Spectrum filters with a wide viewing angle exploiting strong resonance effects in lossy media are demonstrated. The designed filters show significantly improved color purity and the angle-robust characteristic can be preserved up to ±65° due to an interesting phase-cancellation effect. This strategy could provide new routes for numerous applications, such as image sensors and displays.

Ultrathin metal-semiconductor-metal resonator for angle invariant visible band transmission filters

We present transmission visible wavelength filters based on strong interference behaviors in an ultrathin semiconductor material between two metal layers. The proposed devices were fabricated on 2 cm × 2 cm glass substrate, and the transmission characteristics show good agreement with the design. Due to a significantly reduced light propagation phase change associated with the ultrathin semiconductor layer and the compensation in phase shift of light reflecting from the metal surface, the filters show an angle insensitive performance up to ±70°, thus, addressing one of the key challenges facing the previously reported photonic and plasmonic color filters. This principle, described in this paper, can have potential for diverse applications ranging from color display devices to the image sensors.

Microcavity-Integrated Colored Semitransparent Hybrid Photovoltaics With Improved Efficiency and Color Purity

We propose semitransparent amorphous silicon (a-Si)/organic hybrid photovoltaic (PV) cells that can create distinctive transmission colors exploiting a microcavity-integrated cathode. Our proposed PV devices not only produce easily tunable semitransparent colors with considerably enhanced color purity that shows even wider color gamut than the standard red, green, and blue color spaces of the liquid crystal display (LCD) technologies but generate doubled short-circuit current density as well, as compared with a previous work that relied on strong resonance effects in ultrathin semiconductor layers. We also investigate the influence of the thickness of the reflector and the cavity layer inside the microcavity on both optical and electrical performances of the colored hybrid PV cells. This study holds promise in realizing various applications, including color displays with low power consumption and power generating panels with aesthetic functionality.

Ultra-thin intrinsic amorphous silicon/organic hybrid structure for decorative photovoltaic applications

We investigate ultra-thin (6 to 31 nm) intrinsic amorphous silicon (a-Si)/organic hybrid photovoltaic (PV) structures that can produce transmissive or reflective colors, which are insensitive to incidence angle of up to ±70° regardless of polarization. The distinct colors are based on efficient photon manipulation aided by optical resonance in the ultra-thin a-Si photoactive layer. Up to 3% of power conversion efficiency is achieved by using a few tens of nanometer thick a-Si. The proposed hybrid PV structure can be universally applied to other photoactive material systems for higher power efficiency, addressing decorative applications as well.

Ultrathin transmission visible spectrum filters with wide viewing angle

We report high angular tolerant transmission visible spectrum filters exploiting strong resonance behaviors in an ultrathin semiconductor layer between two metals. The angle robust property remains over a wide incident angular range up to ±70°.

Colored hybrid photovoltaics with angle invariance

We present hybrid photovoltaic cells with distinct and angle-insensitive colors based on efficient photon manipulation. Up to 3% of power conversion efficiency is achieved by using tens of nm thick amorphous silicon active layer.

Semi-transparent and colored photovoltaic structures by using ultra-thin a-Si

We exploit optical resonance in an ultra-thin (6 to 31 nm) undoped amorphous silicon/organic hybrid photovoltaic (PV) structures that can produce semi-transparent transmissive colors insensitive to incidence angle of up to ±70° regardless of polarization.

Dual-function ultra-thin a-Si solar cells for color generation and power harvesting

Converting the absorbed light in color filters to electric power is challenging since conventional solar cells are too thick for efficient photon management. We investigate ultra-thin a-Si PVs, producing transmission colors with high angular tolerance.