(Fig.1) Quantum mechanics = parallel worlds is useless for solar cell !
Unfortunately, the current climate change scientists focus only on their vested interests, NOT care about fatal faults in basic science.
This basic science means quantum mechanics, which is based on "fantasy" parallel worlds. Even condensed matter physics pursues "unreality".
The latest Harvard's solar cell is also based on useless quantum mechanics, which is the reason why the current universities are harmful to students, rather than useful.
(Fig.2) Solar cell absorbing light raises an electron to a higher energy state.
In Solar cell, a material such as perovskite absorbs sunlight, and excite their electrons producing pairs of a electron and hole.
Those excited electrons' energy flowing into the external circuit is collected and used. Quantum mechanics cannot describe this mechanism of solar cell in practical way !
(Fig.3) ↓ Effetive mass can be "freely adjustable", unreal, so useless.
In this Harvard paper, they use perovskite solar cell, which is too unstable material to be practical. They use " effective mass", which is NOT a real electron mass !
As shown in this equation (1), they use "unreal effective electron ( hole ) mass" to express the solar cell potential energy.
This effective electron mass is freely changeable to fit experimental results ( this p.3 ), so effective mass approximation cannot predict any physical values !
Because each time we obtain different experimental results, all we can do is change and adjust the effective electron mass to fit these data.
So the "freely-adjustable" effective mass method is useless as actual model to predict other physical values.
Useful model must satisfy the common and fixed principle in any different situations.
(Fig.4) We must use experimental data to predict "real concept" !
In the present quantum mechanics, even when we get some new experimental data, we cannot use them to clarify real physical phenomena !
Instead, quantum mechanics forces us to use these data to create artificial quasiparticle, effective mass .. So our science stops its progress.
This is a very serious problem. We must address it immediately not to increase more educational victims under false science.
(Fig.5) Electron interaction term is freely chosen. ← useless
In larger atoms in condended matter physics, density functional theory (= DFT ) is the only method to compute energies.
It is often said this DFT is successful "ab-initio" method ( this p.3 ).
"Ab-initio" means first-principle which can predict values without empirical parameter ?
Unfortunately this DFT has No ability to predict any values, so useless.
Like this, DFT just chooses some convenient functional out of infinie choices.
In DFT, "exchange correlation functional" means interelectronic repulsions. This functional is unknown, can be freely determined ( this p.2 ).
So DFT can be considered a semi-empirical method, different from media-hype ( this p.23 ), and our basic science stops !
(Fig.6) Experimental data → adjust the value of effective (= unreal ) mass = useless
For some theories to be useful, they have to be able to predict physical values. For that, the basic physical model must be common and applicable to any different conditions.
But in quantum mechanics, when they get different experimental data using different solar cell materials, they just artificially change the values of fake effective mass.
In this Results and discussion, they choose 0.1 me ( or 0.2~0.3 me ) as effective mass ( me is actual electron mass ) in Pb ( or Sn ) - based on solar cells.
And in this Methods, they use density functional theory (= DFT ) to calculate solar cell's energy. We can choose different DFT functionals freely depensing on different materials !
Using "freely-chosen effective mass" and "freely-chosen DFT functional" means this quantum mechanical method is useless and meaningless, cannot predict any useful values !
2016/11/25 updated. Feel free to link to this site.