Efficiency enhancement of solar cells using light management

Abstract

A photovoltaic cell includes a junction, formed from an n-type semiconductor material and a p-type semiconductor material, a trench, opening toward the light-incident side of the junction, for trapping reflected light, and two photon conversion layers. A first photon conversion layer, arranged at the light-incident side of the junction, converts photons from a higher energy to a lower energy suitable for absorption by the semiconductor material, and a second photon conversion layer, arranged at the opposite side of the junction, converts photons from a lower energy to a higher energy suitable for absorption by the semiconductor material.

1 . A photovoltaic cell comprising:
 a junction formed from an n-type semiconductor material and a p-type semiconductor material and having a light-incident side and an opposite side;   a trench, opening toward the light-incident side of the junction, for trapping reflected light;   a first photon conversion layer that converts photons from a higher energy to a lower energy suitable for absorption by the semiconductor material; and   a second photon conversion layer that converts photons from a lower energy to a higher energy suitable for absorption by the semiconductor material.   
     
     
         2 . The photovoltaic cell of  claim 1 , wherein the trench includes a top, a lowermost surface, and at least one plateau elevated above the lowermost surface but disposed below the top of the trench. 
     
     
         3 . The photovoltaic cell of  claim 2 , wherein the trench further includes an additional plateau disposed between the at least one plateau and the top of the trench. 
     
     
         4 . The photovoltaic cell of  claim 2 , wherein the trench further includes an additional plateau disposed between the lowermost surface and the at least one plateau. 
     
     
         5 . The photovoltaic cell of  claim 2 , wherein the at least one plateau is inclined or declined relative to other surfaces of the trench. 
     
     
         6 . The photovoltaic cell of  claim 2 , wherein the lowermost surface is inclined or declined relative to other surfaces of the trench. 
     
     
         7 . The photovoltaic cell of  claim 1 , wherein the second photon conversion layer is arranged on the opposite side of the junction. 
     
     
         8 . The photovoltaic cell of  claim 7 , wherein the first photon conversion layer is arranged on the light-incident side of the junction. 
     
     
         9 . The photovoltaic cell of  claim 8 , wherein the first photon conversion layer is an antireflective coating layer. 
     
     
         10 . The photovoltaic cell of  claim 7 , wherein the second photon conversion layer includes phosphor particles embedded therein, the phosphor particles selected to convert photons passing through the junction unabsorbed from a lower energy to a higher energy. 
     
     
         11 . The photovoltaic cell of  claim 10 , wherein the phosphor particles are nano-particles. 
     
     
         12 . The photovoltaic cell of  claim 10 , wherein the phosphor particles are micro-particles. 
     
     
         13 . The photovoltaic cell of  claim 7 , wherein the second photon conversion layer is a reflective coating layer. 
     
     
         14 . The photovoltaic cell of  claim 1 , wherein the composition of the first photon conversion layer is selected to optimize subsequent absorption of the lower-energy photons, converted thereby, by the semiconductor material. 
     
     
         15 . The photovoltaic cell of  claim 1 , wherein the composition of the second photon conversion layer is selected to optimize subsequent absorption of the higher-energy photons, converted thereby, by the semiconductor material. 
     
     
         16 . The photovoltaic cell of  claim 1 , wherein an upper wall of the trench is inclined or declined relative to other surfaces of the trench. 
     
     
         17 . The photovoltaic cell of  claim 1 , wherein a lower wall of the trench is inclined or declined relative to other surfaces of the trench. 
     
     
         18 . The photovoltaic cell of  claim 1 , further comprising a hollow, opening toward the opposite side of the junction, for minimizing carrier travel path to one or more contacts, for minimizing attenuation of long wavelength light used for up-conversion, or both. 
     
     
         19 . The photovoltaic cell of  claim 18 , further comprising an electrical contact disposed in the hollow. 
     
     
         20 . The photovoltaic cell of  claim 18 , wherein the second photon conversion layer is arranged at least partially in the hollow. 
     
     
         21 . The photovoltaic cell of  claim 1 , wherein at least a portion of the cross-section or profile of the trench is hexagonal in shape. 
     
     
         22 . The photovoltaic cell of  claim 21 , wherein the hexagonally-shaped portion of the trench profile opens directly to the light-incident side of the junction. 
     
     
         23 . The photovoltaic cell of  claim 21 , wherein the hexagonally-shaped portion of the trench profile opens to the light-incident side of the junction via a passage that is narrower than the width of the hexagonally-shaped portion. 
     
     
         24 .- 98 . (canceled)