American scientists have recently confirmed that a single structure can be used to produce hybrid organic-quantum dot light emitting devices (QD-LEDs) that emit light in the visible range. The researchers used ZnCdS and ZnCdSe quantum dots to extend the QD-LED's illumination range to the deep blue and deep red bands while retaining the green and orange-emitting carrier-conducting materials. QD-LEDs deliver saturated, solid colors that are both rugged and durable, while retaining the benefits of high efficiency, flexibility and low cost.
Polina Anikeeva and Jonathan Halpert of the Massachusetts Institute of Technology (MIT) used CdSe, ZnS, ZnSe layers and semiconductor compounds ZnCdS and ZnCdSe to synthesize colloidal quantum dots with a range of luminescence sufficient to cover the visible range. They use an organic substrate that is compatible with all types of quantum dots, and use a simple method to deposit quantum dots on a substrate: first form a quantum dot single layer on the elastomeric seal by spin casting. (QD monolayer), this single layer is printed in the device structure.
Since this method can independently produce quantum dots, the same device structure can be used for quantum dots of various colors. In other words, this QD-LED allows researchers to simultaneously deposit red, green, and blue quantum dots as pixels in a simple and inexpensive step, thus having the potential to be applied to RGB flat-panel displays.
Compared to previous QD-LEDs, the performance of MIT devices increased by four times in green light and by 30% in orange light, thanks to the non-radiation between the substrate organic carrier conductive material and the quantum dots. Non-radiative energy transfer, that is, exciton generated in an organic film, can be efficiently transferred to quantum dots.
Although the MIT team succeeded in finding a series of carrier-conducting materials that can present excitons to green, orange, and red quantum dots, they face the challenge of inefficiency in Blu-ray. The group proposed to improve the exciton energy transfer by designing and synthesizing a wide-gap carrier-conducting organic material, allowing the charge to be directly injected into the blue quantum dots. According to Anikeeva, this type of material is the key to filling the gap between red-orange-green and blue-light QD-LEDs.
Polina Anikeeva and Jonathan Halpert of the Massachusetts Institute of Technology (MIT) used CdSe, ZnS, ZnSe layers and semiconductor compounds ZnCdS and ZnCdSe to synthesize colloidal quantum dots with a range of luminescence sufficient to cover the visible range. They use an organic substrate that is compatible with all types of quantum dots, and use a simple method to deposit quantum dots on a substrate: first form a quantum dot single layer on the elastomeric seal by spin casting. (QD monolayer), this single layer is printed in the device structure.
Since this method can independently produce quantum dots, the same device structure can be used for quantum dots of various colors. In other words, this QD-LED allows researchers to simultaneously deposit red, green, and blue quantum dots as pixels in a simple and inexpensive step, thus having the potential to be applied to RGB flat-panel displays.
Compared to previous QD-LEDs, the performance of MIT devices increased by four times in green light and by 30% in orange light, thanks to the non-radiation between the substrate organic carrier conductive material and the quantum dots. Non-radiative energy transfer, that is, exciton generated in an organic film, can be efficiently transferred to quantum dots.
Although the MIT team succeeded in finding a series of carrier-conducting materials that can present excitons to green, orange, and red quantum dots, they face the challenge of inefficiency in Blu-ray. The group proposed to improve the exciton energy transfer by designing and synthesizing a wide-gap carrier-conducting organic material, allowing the charge to be directly injected into the blue quantum dots. According to Anikeeva, this type of material is the key to filling the gap between red-orange-green and blue-light QD-LEDs.
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