Monolithic integration of cylindrical solar cells

A solar cell unit comprising:

• (A) a substrate, wherein the substrate is either (i) hollowed cylindrical shaped or (ii) a rigid solid rod:
• (B) a first photovoltaic cell comprising:
• a first back-electrode circumferentially disposed on a first portion of said substrate;
• a first semiconductor junction layer circumferentially disposed on said first back-electrode;
• and
• a first transparent conductive layer circumferentially disposed on said first semiconductor junction;
• and
• (C) a second photovoltaic cell comprising:
• a second back-electrode circumferentially disposed on a second portion of said substrate;
• a second semiconductor junction layer circumferentially disposed on said second back-electrode;
• and
• a second transparent conductive layer circumferentially disposed on said second semiconductor junction;
• wherein
• (i) the first photovoltaic cell is adjacent to the second photovoltaic cell;
• (ii) the first transparent conductive layer is in serial electrical communication with the second back-electrode;
• (iii) the first transparent conductive layer is electrically isolated from the second transparent conductive layer;
• and
• (iv) the first back-electrode is electrically isolated from the second back-electrode.

A method comprising:

• passing a fluid through a substrate, wherein
• (A) said substrate has a first end and a second end, wherein the substrate is hollowed cylindrical shaped;
• and
• (B) a plurality of photovoltaic cells are linearly arranged on said substrate, the plurality of photovoltaic cells comprising a first photovoltaic cell and a second photovoltaic cell, each photovoltaic cell in said plurality of photovoltaic cells comprising:
• a back-electrode circumferentially disposed on said substrate;
• a semiconductor junction layer circumferentially disposed on said back-electrode;
• and
• a transparent conductive layer circumferentially disposed on said semiconductor junction, wherein
• the transparent conductive layer of the first photovoltaic cell in said plurality of photovoltaic cells is in serial electrical communication with the back-electrode of the second photovoltaic cell in said plurality of photovoltaic cells.