Did you know that the first solar cell patent was granted all the way back in 1888? From the late 19th century to 2011, solar energy has made great leaps and bounds.
and then identifies the "first solar cell patent" as
The First Solar Cell Patent
US Patent 389,124
and further writes:
A prolific inventor, Edward Weston would patent 334 different inventions before his death in 1936. In 1888, he published his “Apparatus for Utilizing Solar Radiant Energy” in Newark, New Jersey. That same year Russian physicist Aleksander Grigorievich constructed the first solar cell based on Weston’s models using the basic principles of Heinrich Hertz’s photoelectric effect.
Within Weston's US Patent 389,124, the first claim is to a combination of
a means to concentrate light thereupon and
a storage cell.
The specification makes clear that the thermopile is a set of thermocouples,
joined in series.
Thermocouples generate voltages because of temperature differences between dissimilar metals.
One can find on wikipedia:
A thermopile is an electronic device that converts thermal energy into electrical energy. It is composed of several thermocouples connected usually in series
A solar cell (also called photovoltaic cell or photoelectric cell) is a solid state device that converts the energy of sunlight directly into electricity by the photovoltaic effect.
Most people would not consider that Weston's US Patent 389,124 describes a solid state device that converts the energy of sunlight directly into electricity.
Wikipedia also notes: However, it was not until 1883 that the first photovoltaic cell was built, by Charles Fritts, who coated the semiconductor selenium with an extremely thin layer of gold to form the junctions. The device was only around 1% efficient. In 1888 Russian physicist Aleksandr Stoletov built the first photoelectric cell (based on the outer photoelectric effect discovered by Heinrich Hertz earlier in 1887).
Of another bad post on solar cells:
An infinity of stupidity?
**Merely as background on thermocouples, from wikipedia:
In 1821, the German–Estonian physicist Thomas Johann Seebeck discovered that when any conductor is subjected to a thermal gradient, it will generate a voltage. This is now known as the thermoelectric effect or Seebeck effect. Any attempt to measure this voltage necessarily involves connecting another conductor to the "hot" end. This additional conductor will then also experience the temperature gradient, and develop a voltage of its own which will oppose the original. Fortunately, the magnitude of the effect depends on the metal in use. Using a dissimilar metal to complete the circuit creates a circuit in which the two legs generate different voltages, leaving a small difference in voltage available for measurement. That difference increases with temperature, and is between 1 and 70 microvolts per degree Celsius (µV/°C) for standard metal combinations.
The voltage is not generated at the junction of the two metals of the thermocouple but rather along that portion of the length of the two dissimilar metals that is subjected to a temperature gradient. Because both lengths of dissimilar metals experience the same temperature gradient, the end result is a measurement of the temperature at the thermocouple junction.
**In passing, Aleksandr Grigoryevich Belyavskiy is a Russian football player.
**See also Energy demand and climate change: issues and resolutions By Franklin H. Cocks, with the text "Solar cells convert the energy in sunlight directly into electricity." Note also Figure 6.1 on thermoelectric devices.